The sex ratio of male to female dragonflies varies both temporally and spatially. Adult dragonflies have a high male-biased ratio at breeding habitats. The male-bias ratio has contributed partially to the females using different habitats to avoid male harassment. As seen in Hine's emerald dragonfly ("Somatochlora hineana"), male populations use wetland habitats, while females use dry meadows and marginal breeding habitats, only migrating to the wetlands to lay their eggs or to find mating partners. Unwanted mating is energetically costly for females because it affects the amount of time that they are able to spend foraging.
Sex ratios
Dragonfly
Dragonfly | Sex ratios
The sex ratio of male to female dragonflies varies both temporally and spatially. Male to female dragonflies varies both temporally and spatially, adult have a high male-biased ratio at breeding habitats The sex ratio of male to female dragonflies varies both temporally and spatially. Adult dragonflies have a high male-biased ratio at breeding habitats. The male-bias ratio has contributed partially to the females using different habitats to avoid male harassment. The sex ratio of male to female dragonflies varies both temporally and spatially
what are the life stages of a dragonfly
user
Dragonflies are hemimetabolous insects; they do not have a pupal stage and undergo an incomplete metamorphosis with a series of nymphal stages from which the adult emerges.
assistant
what are they ?
user
It is an insect belonging to the order Odonata, infraorder Anisoptera.
assistant
any conservation efforts to protect it ?
user
In 1997, the International Union for Conservation of Nature set up a status survey and conservation action plan for dragonflies.
assistant
talk about their coloration ?
user
It is often a combination of yellow, red, brown, and black pigments, with structural colours.
assistant
what are its behavior patterns ?
user
Many dragonflies, particularly males, are territorial. Some defend a territory against others of their own species, some against other species of dragonfly and a few against insects in unrelated groups.
assistant
what about its sex ratios ?
user
The sex ratio of male to female dragonflies varies both temporally and spatially. Adult dragonflies have a high male-biased ratio at breeding habitats. The male-bias ratio has contributed partially to the females using different habitats to avoid male harassment. As seen in Hine's emerald dragonfly ("Somatochlora hineana"), male populations use wetland habitats, while females use dry meadows and marginal breeding habitats, only migrating to the wetlands to lay their eggs or to find mating partners. Unwanted mating is energetically costly for females because it affects the amount of time that they are able to spend foraging.
Dragonfly | Sex ratios
Due to the need to fight off other males in order to be more successful in breeding, male dragonflies have developed extensive flight muscles. The majority of male Plathemis lydia dragonflies body mass is accounted for by flight muscle, and is one of the highest flight-muscle ratio (FMR, found by flight-muscle mass/body weight) of an animal. Males with smaller FMRs have a slight decrease in mating success when compared to their counterparts. This decrease in success found in males with a smaller FMR can be contributed to a decrease in the ability to compete in aerial contests. However, a tradeoff must be made in order to have a larger FMR.
Common whitetail | Mating
Males that were found to have the highest FMR had the least amount of gut contents, and in turn less fat reserves. This means that the male dragonflies are making a tradeoff between flight ability and longevity, which may affect long-term mating success. The act of copulation begins with the male clasping the neck of the female. The female then bends her abdomen forward into the secondary genitalia of the male, which is located on the second abdominal segment. Once the female has moved into this position (known as the "wheel position"), the male is able to remove the sperm of any prior mates, and transfer his own sperm to the female.
Common whitetail | Mating
Mating in dragonflies is a complex, precisely choreographed process. First, the male has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers a packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating. The pair flies in tandem with the male in front, typically perching on a twig or plant stem.
Dragonfly | Reproduction
A female must mate with the territory holder before laying her eggs. There is also conflict between the males and females. Females may sometimes be harassed by males to the extent that it affects their normal activities including foraging and in some dimorphic species females have evolved multiple forms with some forms appearing deceptively like males. In some species females have evolved behavioural responses such as feigning death to escape the attention of males. Similarly, selection of habitat by adult dragonflies is not random, and terrestrial habitat patches may be held for up to 3 months. A species tightly linked to its birth site utilises a foraging area that is several orders of magnitude larger than the birth site.
Dragonfly | Behaviour
Male homosexuality has been inferred in several species of dragonflies (the order Odonata). The cloacal pinchers of male damselflies and dragonflies inflict characteristic head damage to females during sex. A survey of 11 species of damsel and dragonflies has revealed such mating damages in 20 to 80% of the males too, indicating a fairly high occurrence of sexual coupling between males.
Homosexual behavior in animals | Dragonflies
The species typically has a sex ratio that is biased towards males (usually in a 2:1 ratio). This is attributed to the relative size of the host ants, which happen to have more large individuals than smaller individuals. There is a lower number of hosts that can support the development of female flies, making the female gender rarer. This creates intraspecific competition between the "P. tricuspis" females who compete with each other in trying to oviposit within the same host. The females exhibit aggressive and territorial behavior.
Pseudacteon tricuspis | Sex ratio
The female then curls her abdomen downwards and forwards under her body to pick up the sperm from the male's secondary genitalia, while the male uses his "tail" claspers to grip the female behind the head: this distinctive posture is called the "heart" or "wheel"; the pair may also be described as being "in cop". Egg-laying (ovipositing) involves not only the female darting over floating or waterside vegetation to deposit eggs on a suitable substrate, but also the male hovering above her or continuing to clasp her and flying in tandem. The male attempts to prevent rivals from removing his sperm and inserting their own, something made possible by delayed fertilisation and driven by sexual selection.
Dragonfly | Reproduction
The adult male abdomen measures 21–24 mm and hind wing 24–27 mm. Female abdomen measures 23 mm and hind wing 26–30 mm. The male is a medium-sized scarlet dragonfly with a broad reddish amber patch on the base of transparent wings. The female is similar to the male, but duller in color. Its natural habitats are subtropical or tropical streams and rivers. It breeds in marshes, ponds, and lakes, and prefers to perch on exposed rocks, dry areas, and boulders in riverbeds.
Trithemis kirbyi | Description and ecology
It is a small dragonfly with brown capped greenish eyes. Its thorax is greenish yellow and hind-wings usually tinted with yellow from the base. Pterostigma is black in adults bi-colored in juveniles and sub-adults as in females. Its abdomen is pruinosed with light blue, leaving segments 1-3 as yellow. Sub-adult males and females are yellow. The pterostigma of the female are bi-colored with half black and half yellow. It breeds in marshy areas and small pools in the hills.
Palpopleura sexmaculata | Description and habitat
In dragonflies, it is a set of modified sternites on the second abdominal segment. In advanced groups of insects, the male uses its aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a "spermatophore") into the female's reproductive tract.
Sexual intercourse | Other animals
Mating in damselflies, as in dragonflies, is a complex, precisely choreographed process involving both indirect insemination and delayed fertilisation. The male first has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers a packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating.
Damselfly | Reproduction
Dragonflies and damselflies are predatory both in the aquatic nymphal and adult stages. Nymphs feed on a range of freshwater invertebrates and larger ones can prey on tadpoles and small fish. Adults capture insect prey in the air, making use of their acute vision and highly controlled flight. The mating system of dragonflies is complex and they are among the few insect groups that have a system of indirect sperm transfer along with sperm storage, delayed fertilization, and sperm competition. Adult males vigorously defend territories near water; these areas provide suitable habitat for the larvae to develop, and for females to lay their eggs.
Dragonfly | Ecology
The females cannot yet be told apart. The length of this dragonfly is from and the span of the hindwings is .
Brachythemis impartita | Description
The female mates once and stores all the sperm she needs for fertilization. If she should mate again, the second male will remove the sperm of the first male from her body with the brush-like apparatus on his specially-adapted penis. The larvae of the dragonflies hatch and eat anything they can catch, favoring a carnivorous diet of organisms smaller than themselves. Adults of the species, especially males, congregate in swarms. Some populations of this dragonfly undertake migrations. Both the larvae and adult forms are efficient predators of mosquitoes, so they are a helpful insect to have in wet areas where mosquito infestations occur.
Black saddlebags | Introduction
Many dragonflies, particularly males, are territorial. Some defend a territory against others of their own species, some against other species of dragonfly and a few against insects in unrelated groups. A particular perch may give a dragonfly a good view over an insect-rich feeding ground; males of many species such as the "Pachydiplax longipennis" (blue dasher) jostle other dragonflies to maintain the right to alight there. Defending a breeding territory is common among male dragonflies, especially in species that congregate around ponds. The territory contains desirable features such as a sunlit stretch of shallow water, a special plant species, or the preferred substrate for egg-laying.
Dragonfly | Behaviour
The female flies with the male still attached after mating (a position called "in tandem") and lays her eggs near the shoreline of lakes and ponds by dipping the tip of her abdomen on the surface of the water. Large-mouth bass ("Micropterus salmoides") have been observed following mated pairs of dragonflies as they fly just above the surface, and then eating them as they touch the surface to lay eggs.
Sympetrum vicinum | Reproduction
The nymphs moult repeatedly, at the last moult climbing out of the water to undergo metamorphosis. The skin splits down the back, they emerge and inflate their wings and abdomen to gain their adult form. Their presence on a body of water indicates that it is relatively unpolluted, but their dependence on freshwater makes them vulnerable to damage to their wetland habitats. Some species of damselfly have elaborate courtship behaviours. Many species are sexually dimorphic, the males often being more brightly coloured than the females. Like dragonflies, they reproduce using indirect insemination and delayed fertilisation. A mating pair form a shape known as a "heart" or "wheel", the male clasping the female at the back of the head, the female curling her abdomen down to pick up sperm from secondary genitalia at the base of the male's abdomen.
Damselfly | Introduction
Due to the need for the female to enter the wheel position, males cannot force themselves onto females. Post mating, male Plathemis lydia dragonflies will perform "non-contact mate-guarding throughout oviposition". During this time, the male dragonflies will hover roughly 0.5-1m away from their mate, and chase off any rival males that may be attempting to mate with the female. The intensity at which males guard females is positively correlated with the frequency of male harassment that occurs during the oviposition. However, males tend to guard less intensely over the course of the oviposition process, and will stop guarding entirely once it has finished.
Common whitetail | Mating
If successful, a rival male uses his penis to compress or scrape out the sperm inserted previously; this activity takes up much of the time that a copulating pair remains in the heart posture. Flying in tandem has the advantage that less effort is needed by the female for flight and more can be expended on egg-laying, and when the female submerges to deposit eggs, the male may help to pull her out of the water. Egg-laying takes two different forms depending on the species. The female in some families has a sharp-edged ovipositor with which she slits open a stem or leaf of a plant on or near the water, so she can push her eggs inside.
Dragonfly | Reproduction
"Brachythemis impartita" has a pale cream pterostigma in both sexes and their eyes appear to be striped. The female has a buffy abdomen and thorax, males are darker and mature males can be dark blue to black on the abdomen and thorax. Males have bands on the outer wings from the node to just short of the pterostigma, this is paler in teneral individuals but darkens as the dragonfly matures. Where they overlap with "B. leucosticta" the males can be distinguished by the colour of the veins and the genital lobe, as well as by the ventral structure of segment 8.
Brachythemis impartita | Description
Every few days, female "Plathemis lydia" dragonflies will go to ponds in order to lay their eggs, also known as ovipost. Male dragonflies that are defending mating territories at the ponds will then attempt to mate with the female dragonflies. While the females are at the pond to ovipost, they will actively discriminate against the males attempting to mate with them, rejecting up to 48.9% of all mating attempts. The females prefer to ovipost in the middle of the day, and will actively look for particular parts of the pond to find a more suitable place to lay their eggs.
Common whitetail | Mating
Male: Key features for identification of the males are the shape of the cerci (appendages at the end of the abdomen of males) and the pattern of the markings on the thorax. The ends of the cerci diverge, and they are thick and truncate. In southern Africa (south of 15°S), the shape of the cerci separate this species from other dragonflies.
Paragomphus cognatus | Identification
Before reproduction can occur, a male must first establish a territory. These territories range from 2–4 meters in area and sit close to bodies of water. Male dragonflies patrol these areas and defend them from dragonflies of both their own and other species. Females initiate mating by flying into a male’s territory. A male responds to this behavior by chasing after the female. Once the male reaches the female, he latches onto her body. The two then fly to nearby shrubs, and copulation begins. Post-copulation, the female repeatedly dips her abdomen into shallow water. In doing so, she deposits her fertilized eggs.
Hine's emerald | Reproduction
The flight period is from April to September but are mostly seen in May and June. Their flight is very fast as they dart and dive above the water. They are very territorial and will fight with rival males and any other dragonflies they happen to encounter. They characteristically return to a favoured perch, in the sun. When a female enters a male's territory the male will fly up and grab the female. Mating occurs on the wing and the pair are in tandem for only a brief period, often less than a minute. The pair separate and the female will find a suitable location for ovipositing, usually a stretch of open water with submerged vegetation.
Libellula depressa | Behaviour
Many non-human animals have been shown to be able to distinguish between potential partners, based upon levels of FA. As with humans, lower levels of FA are seen in the most reproductively successful members of species. For instance, FA of male forewing length seem to have an important role in successful mating for many insect species, such as dark-wing damselflies and Japanese scorpionflies. In the dark-winged damselfly ("Calopteryx maculate"), successfully mating male flies showed significantly lower levels of FA in their forewings than unsuccessful males, while for Japanese scorpionflies, FA levels are a good predictor for the outcome of fights between males in that more symmetrical males won significantly more fights.
Fluctuating asymmetry | Sexual selection in non-human animals
The adults of "Onychogomphus forcipatus" grow up to long, with a wingspan of . The eyes of these medium sized dragonflies are widely separated and grey-to-green. The two black lines on the side of the thorax are relatively narrow and touch the midline. It has a yellow line on the vertex and two cells above the anal triangle. The abdomen in males is fitted with three hooks of large size (anal appendages). Cercoids may be dark and have a subterminal tooth. The base of the hindwing is angled in males and rounded in females. This species is rather similar to "Onychogomphus uncatus".
Onychogomphus forcipatus | Description
"G. flavipes", as all dragonflies, are predators; they capture smaller insect in flight. Imagos are rarely seen, the easiest way to observe them is in the mating period or during the emergence of young adults. Mating usually takes place in June or July. During the day adult males search for females, far from the riverbank, in low altitude above the waterfront. If they successfully catch a female copulation takes place in the shelter of water edge willows. After fertilization females fly 20–30 cm above the water and lay eggs (one at a time or in a small packets) into the water.
Gomphus flavipes | Behaviour and life cycle
There is sexual dimorphism in Drone-flies where males tend to have lighter patterns than females. Males can also be easily distinguished from females by their larger eyes that almost touch each other, whereas females have smaller eyes that are spaced father apart.
Eristalis tenax | Sexual dimorphism
The abdomen is swollen where it joins the body, then forms a distinctive waist of about 2 mm at segment 3. This waist is about half the width of segment 2, the segment closer to the main body. Beyond the waist, the abdomen tapers to the end. The second segment of the abdomen on a male has light green auricles, miniature ear-like projections on each side. At the tip of their tails male dragonflies of the genus "Gynacantha" have a distinctive pair of long, slim, anal appendages with fine hairs on their inner sides. These hold the female during mating.
Gynacantha rosenbergi | Abdomen
However, she then allows the male to come closer and place his mandibles over her wings in a perpendicular position, a position he holds until the female signals reception to mating. At least in "Protohermes", during copulation the male attaches to the female's genitalia a large, globular spermatophore about 4 mm long and wide. The spermatophore consists of two parts: a large gelatinous mass, and a smaller seminal duct containing the sperm. After copulation, the female proceeds to spread her legs wide apart, curl the abdomen under the chest, and eat the gelatinous part of the spermatophore. Oviposition occurs along rocky walls of streams at night, from May to September in "Corydalus".
Dobsonfly | Life cycle
This dragonfly is 24 to 34 millimeters long, with a hindwing 25 to 30 millimeters long. It can be identified by the brown spots at the bases and tips of the wings. The pterostigma is yellow in younger individuals, and red in older. The face is yellow, turning red in older male specimens. The thorax is yellow-brown with a large dark stripe and several smaller brown stripes. The abdomen is dark with paler markings.
Celithemis elisa | Description
Gynacantha sextans is a species of dragonfly in the family Aeshnidae. It is found in Angola, Cameroon, the Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Ghana, Guinea, Nigeria, Uganda, and Zambia. Its natural habitats are subtropical or tropical moist lowland forests and shrub-dominated wetlands.
Gynacantha sextans | Introduction
The ratio appears to be even more evident in observations of roosting or migrating monarchs, where fewer than 30% of the monarchs are females.
Monarch butterfly migration | Sex ratios
As a medium-sized dragonfly "G. flavipes" is 50–55 mm long and with an average wingspan of 70–80 mm. The eyes are widely separated, this is a typical genus-specific feature, males have blue while females have green eyes. Both sexes have predominantly yellow legs and the males has thin angled appendages, while his 10th segment is entirely black dorsally.
Gomphus flavipes | Morphology
The abdomen is long and cylindrical in many species, but in the Libellulidae it may be relatively short and broad. It has ten segments (S1-S10), terminating with appendages on S10. Males have both upper appendages (cerci) and lower appendages (epiprocts in dragonflies and paraprocts in damselflies), which are used to hold females while mating; these are also termed claspers. Males also have secondary genitalia (including the anterior lamina, hamuli and posterior lamina) on S2 and S3. Female damselflies and some dragonflies have a strong ovipositor on the underside of S8 and S9, but in many dragonflies the egg-laying apparatus is merely a spout, a basket, or a pair of flaps.
External morphology of Odonata | Abdomen
The determination of sex in "E. socialis" is chromosomal with heterogametic females. But, the primary sex-ratio i.e., the sex-ratio at conception is extremely male-biased with an average of about 70% males. This bias has been observed in both the eastern and western sub-populations, and is thought to be caused by meiotic instability. Furthermore, the operational sex-ratio is also male-biased. Such a ratio is thought to be evolutionarily maintained because of the selective advantage of male-biased groups in the communal nests.
Madrone butterfly | Sex-ratio
For example, in "Coenagrion", the Eurasian bluets, the males are bright blue with black markings, while the females are usually predominantly green or brown with black. A few dimorphic species show female-limited polymorphism, the females being in two forms, one form distinct and the other with the patterning as in males. The ones that look like males, andromorphs, are usually under a third of the female population but the proportion can rise significantly and a theory that explains this response suggests that it helps overcome harassment by males. Some Coenagrionid damselflies show male-limited polymorphism, an even less understood phenomenon. In general, damselflies are smaller than dragonflies, the smallest being members of the genus "Agriocnemis" (wisps).
Damselfly | General description
Males can be observed flying in a nearly vertical orientation; their antennae held forward and stiff while their legs are held toward the body during patrolling. They also show an obvious gaze shift towards the last female flash, and continue towards it until the female firefly flashes again. The flashes continue until the male reaches the female. Males congregate in large masses and it is most likely that more than one will find the same female; in this case male "P. pyralis" display aggression towards one another while not in flight. During the “aggression” stage, males with smaller elytra and smaller lanterns are favored; whereas during the signaling phase, males with longer elytra and bigger lanterns are favoured.
Photinus pyralis | Mating
Male homosexuality has been inferred in several species of dragonflies. A survey of damsel and dragonflies reveals characteristic cloacal pincher mating damage in 20–80 percent of the males, indicating a fairly high occurrence of sexual coupling between males.
List of animals displaying homosexual behavior | Insects
The male is usually still attached to the female at this point to stop other males from removing their sperm, although sperm removal is harder in "C. scitulum" as they do not have the spines on the horns of their penis as other damselflies do. The dainty damselfly seems to be univoltine in their core populations and in their expansion populations, this was exhibited when ponds were sampled and they showed that each was a separate population.
Dainty damselfly | Reproduction
"Crocothemis erythraea" can reach a length of . These dragonflies haves a flattened and rather broad abdomen. The adult male scarlet dragonfly has a bright scarlet red, widened abdomen, with small amber patches at the bases of the hindwings. Also the veins on the leading edges of the wings are red. Females and immatures are yellow-brown and have a conspicuous pale stripe along the top of the thorax.
Scarlet dragonfly | Description
The flight period extends from April to mid October, but this dragonfly is more common in late summer. Adults feed on soft-bodied flying insects. After mating females usually fly in tandem with males during oviposition, performed in flight by dipping the tip of the abdomen into the water. Larvae live in aquatic vegetation. They feed on many different aquatic insects (mosquito larvae, mayfly larvae, other fly larvae, small fish and tadpoles).
Band-winged meadowhawk | Biology and behavior
"Diplacodes bipunctata" is a small to medium-sized dragonfly with a wingspan of about 55 millimeters. The wings are colorless except for a yellowish spot at the base of the hindwing. The male has a bright orange or red abdomen with dark markings along the dorsal line and sides, and the female is yellowish with similar markings. There are two dark spots at the side of the synthorax, one of which is the metastigma.
Diplacodes bipunctata | Description
As is usual in the Libellulidae family, there is no distinct courtship ritual. The females may pair many times, but usually only once a day. After mating, the migrant dragonflies fly in tandem, with the female ovipositing while the male remains connected. A clutch consists of about 500 to 2000 eggs. The eggs are spheroid in shape with the semi-major axis 0.5 mm and 0.4 mm at the smallest points. The larvae develop within 38 to 65 days, which allows this migrant dragonfly to reproduce in temporary waters or even in swimming pools. However, the larvae seem to be very sensitive to temperature.
Pantala flavescens | Reproduction and development
"Diplacodes nebulosa" is a very small and slender dragonfly. Males have a black abdomen and black wing tips; females are yellow and black, and their wings can be hyaline, or with an orange base, or, like the male, have black tips. It prefers marshes and heavily weeded ponds.
Diplacodes nebulosa | Description and habitat
Females cannot hunt for food: they only receive protein from nuptial gifts brought to them by males. Female dependence on males for nutrition is the principle cause for sex role reversal in this species of fly. Males hunt an hour before sunset within a range of 30m from the lek site. They rapidly scour the area in a figure-8 flight pattern looking for food. Males will eat any prey they can find, but they normally capture swarming insects. More specifically, most tend to prey on flies ("Diptera)", which make up 70% of their combined prey. They also feed on mayflies ("Ephemeroptera") and caddisflies ("Trichoptera"), and infrequently feed on male ants, moths,[2] and mosquitoes.
Rhamphomyia longicauda | Food resources
After mating, a male guards a female to prevent other males from mating with her. He does this by flying above her while she laying her eggs. It drives away other potential mates or maybe dragonflies of other species. The female lays her eggs by dipping the tip of her abdomen in the water while hovering above the surface.
Hudsonian whiteface | Reproduction
Several years of their lives are spent as nymphs living in fresh water; the adult stage of some dragonflies may be as long as ten weeks, but most species have an adult lifespan on the order of five weeks or less, and some last only a few days. They are fast, agile fliers, sometimes migrating across oceans, and often live near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilization, and sperm competition. During mating, the male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male's secondary genitalia at the front of his abdomen, forming the "heart" or "wheel" posture.
Dragonfly | Introduction
Mating occurs either on floating plants or at the margins. When perched on floating plants, the male holds its abdomen slightly upcurved (the red-eyed damselfly holds it straight).
Small red-eyed damselfly | Behaviour
It is a medium sized dragonfly with thorax black on dorsum, and yellow on the sides. There is a slightly oblique ante-humeral stripe and two narrow parallel black stripes on the sutures enclosing an equally narrow yellow line. Abdomen is black, marked with yellow. Segment 1 has a large spot on the dorsum and the sides. Segment 2 has a mid-dorsal spot. Segment 3 to 7 have basal rings, narrow on 3 to 6, occupying the basal half on segment 7. Segment 8 to 10 are unmarked. Anal appendages are yellow, black on the base. This species is found in banks of montane forest streams where it breeds.
Davidioides martini | Description and habitat
It is a large dragonfly characterized by its homogeneous colouring of dull browns and greens, by its long and thin anal appendages, and by its crepuscular habits. Its principal food appears to be mosquitoes and microlepidoptera. During the day it rests in dark thickets. Fully matured specimens have bright colours; blues and greens developing very late in life. Young specimens have brown color with some dark shades. Females are exactly similar to the males in colors and markings. It is very closely related to "G. subinterrupta" and it is difficult to distinguish them. But the relative lengths of the superior and inferior anal appendages are different.
Gynacantha dravida | Description and habitat
"Orthetrum testaceum" can reach a body length of about , with an hindwing of (in males). In these large dragonflies the thorax of adult males is orange-brown, with a vermilion red abdomen. The eyes are light brownish. The wings are smoky transparent, with an amber patch at the base. In adult females and in recently emerged males body is olive-green to brown in colour with black markings and a clear base of the hindwings. These dragonflies are rather similar to "Orthetrum chrysis", but "O. testaceum" is much reddish, whilew "O. chrysis" has a reddish brown thorax.
Orthetrum testaceum | Description
An unusual pattern has been observed in the sex ratios of monarchs in the eastern North American population, both during the fall migration and at the overwintering sites in Mexico. Normally during the breeding season, the ratio of males and females is roughly the same, but during the migration the ratio is skewed toward males. This persists during the overwintering period as well, likely because it's the same cohort that advances from migration to the overwintering sites. Scientists have examined records from the overwintering period over 30 years, and found that the skewed sex ratio has grown more pronounced in recent years, perhaps because of a loss of females.
Monarch butterfly migration | Sex ratios
In other families such as clubtails (Gomphidae), cruisers (Macromiidae), emeralds (Corduliidae), and skimmers (Libellulidae), the female lays eggs by tapping the surface of the water repeatedly with her abdomen, by shaking the eggs out of her abdomen as she flies along, or by placing the eggs on vegetation. In a few species, the eggs are laid on emergent plants above the water, and development is delayed until these have withered and become immersed.
Dragonfly | Reproduction
Many damselflies have elaborate courtship behaviours. These are designed to show off the male's distinctive characteristics, bright colouring or flying abilities, thus demonstrating his fitness. "Calopteryx" males will hover in front of a female with alternating fast and slow wingbeats; if she is receptive she will remain perched, otherwise she will fly off. The male river jewelwing ("Calopteryx aequabilis") performs display flights in front of the female, fluttering his forewings while keeping his hindwings still, and raising his abdomen to reveal the white spots on his wings. "Platycypha" males will hover in front of a female, thrusting their bright white legs forward in front of their heads.
Damselfly | Behaviour
The male and female have a broad, flattened abdomen which is brown with yellow patches down the sides. In the male the abdomen develops a blue pruinosity that covers the brown colour. Both fore and hind wings have a dark patch at the base. Both the male and female have broad antehumeral stripes. The average wingspan is approximately 70 mm. "L. depressa" is very distinctive and should not be confused with any other dragonflies in the region.
Libellula depressa | Identification
A large dragonfly (length 61–64 mm; wingspan 87–91 mm). The eyes are green and the face deep yellow to greenish yellow; the upper frons has a central black spot within a yellow ring. The thorax is brown with green stripes, and the abdomen green with brown markings. The wings are slightly smoky with brown and yellow veins and reddish-brown to yellow-brown pterostigmata.
Pinheyschna subpupillata | Description
The adults have metallic bodies; their wings are broader, with wider bases than other damselflies, and at rest hold their wings parallel to the body, slightly elevated. Some species have conspicuously colored wings; in males, the wings are usually blue, without pterostigmas, in females green or brown. Species are often quite variable in color and patterning, and they are sexually dimorphic. Color intensity may fade with age. The wings are heavily veined, having often 18 or more antenodal veins. The first segment of their antennae is longer than the combined length of the other segments. They have a jerky, skipping form of flight (fluttering, rather than hovering stably like many other damselfly and dragonfly families).
Calopterygidae | Characteristics
Many species exhibit marked sexual dimorphism: males and females are coloured and patterned differently from each other, and (in addition to the spine filament) males have a much higher dorsal fin. This difference is extreme in the high-finned dragonet ("Synchiropus rameus").
Dragonet | Physical description
There is a sex ratio bias in "A. agilissima", skewed towards having more females than males. This may be due to local mate competition which means that males essentially devalue each other by competing for the same females as mates. This is only really true for mating within the tunnels before emergence where they are closer to their nest and not as visible compared to when there is mating at flowers away from the nest.
Andrena agilissima | Sex ratios
It is a medium sized dragonfly with brown-capped grey eyes. Its thorax is cinereous, marbled and peppered with black in a very irregular manner. Wings are transparent with dual color pterostigma, black at centre and pure white at distal and proximal ends. Abdomen is coloured very similarly to thorax; black marbled with yellow, but with a more definite plan. Segments 3 to 8 have pale basal annules interrupted on dorsum, and formed by two elongate parallel spots. There is a triangular apical sub-dorsal spot and a pale mid-dorsal spot. Anal appendages are creamy-white. Female is similar to the male. Taking advantage of its cryptic coloration, it always rests flat on slab rock or cement-plastered walls, where it almost invisible.
Bradinopyga geminata | Description and habitat
When they first emerge, both sexes appear pale green with brown markings. The legs are brown with a yellow like base. Wings are born black but grow yellow-brown with age. Males have a sky blue abdomen marked with a diagnostic black dorsal stripe and an apple green thorax. The thorax and head of a male is green and their prominent eyes are blue. Females have similar markings but they are mainly green.
Emperor (dragonfly) | Identification
It is a medium-sized dragonfly with brown capped eyes, greenish brown thorax and bluish abdomen. Female lacks the powder blue pruinescence. It prefers medium to slow-flowing streams in the dry zones and hot plains. Adults are common around open rocky and sandy beds of the streams.
Orthetrum taeniolatum | Description and habitat
It is a small dragonfly with bottle-green eyes. Its thorax is black with slightly interrupted mesothoracic collar and narrow ante-humeral stripes. There is a broad black stripe on postero-lateral suture. Abdomen is black, marked with greenish yellow. Segment 1 has a narrow apical border. Segment 2 has a broad basal ring. Segments 3 to 6 have narrow basal rings. Segment 7 is similar, but broader. Segments 8 to 10 are unmarked. Female is similar to the male. It looks similar to "Microgomphus torquatus"; but can be distinguished by the marks on thorax and by the shape of the anal appendages.
Microgomphus souteri | Description and habitat
It is a medium sized dragonfly with red eyes, thorax and abdomen. But young males and females have a mid-dorsal citron-yellow stripe in the pro-thorax and a citron-yellow stripe on mid-dorsum of the abdominal segments. These marks get obscured by pruinescence in adult males. Color of female is brown. It breeds in open ponds, marshes and lakes.
Rhodothemis rufa | Description and habitat
The 9th tergite is like the rest of the abdomen but has a pair of cerci for mating. Cerci are like claspers (which dragonflies possess) that help the male get a grasp of the female during copulation. Females have a duller outlook. They are a light brown with red spines covering the entire thorax and the top of the head. (Males have an absence of spines on the head). The femur has spines on the edges but not colourful like the males. There are a few patches of light cyan on the coxa, the inner part of the femur and sometimes the head.
Achrioptera fallax | Description
"Lestes congener" can reach a length of in males, while females are smaller, reaching a length of . In the western part of their range, these dragonflies are somewhat larger than in the eastern part. The thorax is slaty gray dorsally, with two dark elongated spots (hence the common name) on the latero-ventral surface. The eyes are blue in males, while in the females they are always brown. The abdomen is greyish to blackish with bronze reflections, the last two segments of the abdomen are pale gray. The wings are clear and transparent. Like other damselflies of the family Lestidae they hold their wings at about 45 degrees to the body when resting.
Lestes congener | Description
Family Calopterygidae (demoiselles) Family Lestidae (emerald damselflies or spreadwings) Family Coenagrionidae (blue, blue-tailed and red damselflies)
List of dragonflies of Menorca | Suborder <a href="Damselfly">Zygoptera (damselflies)</a>
Courtship behaviors observed in both female and male "H. mycetophaga" are similar to those found in other flies of the same genus. Prominent wing displays are the primary similarity between the two. Both sexes move their abdomen up and down during courtship rituals, and have been observed to touch tarsi with each other. They will also sometimes attempt to use their middle and fore legs to trample the fly that they are oriented towards. Additionally, both males and females extend one wing 90 degrees in displays. The presence of female wing display in this species is noteworthy; previously, this had only been noted in the "lesbian" mutant phenotype of "D.
Hirtodrosophila mycetophaga | Overlapping behaviors between sexes
It is a medium-sized dragonfly with dark thorax with slight purple pruinescence and purple colored abdomen. Young males have red abdomen as in "Orthetrum chrysis". Females of both species look similar. It breeds in ponds, lakes and sluggish streams.
Orthetrum pruinosum | Description and habitat
In groups that have reproduction similar to spiders, such as dragonflies, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified sternites on the second abdominal segment. In advanced groups of insects, the male uses its aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a "spermatophore") into the female's reproductive tract.
Copulation (zoology) | In spiders and insects
It is a yellowish red dragonfly with reddish brown eyes. It has a broad basal amber-yellow marking at base of all wings. Its abdomen is reddish with a ventro-lateral brownish stripe interrupted at apical end of segments 3 to 8. Young males and females are more yellowish red. It is more common at sea level all along the coast but becoming rare in the hills.
Neurothemis intermedia | Description and habitat
It is a large reddish-brown dragonfly with golden-amber tinted wings. Eyes are reddish-brown above, yellowish below. Its thorax is ohvaceous suffused with golden reddish-brown, Its base of hind-wings have a moderately broad dark reddish-brown mark. Abdomen is olivaceous, changing to ochreous towards anal end, marked with black. Segments 4 to 9 have apical and basal dorsal black wedge-shaped spots. It breeds in weedy ponds and lakes. The male is often seen patrolling over water, and rarely perches. When perched, they prefer to hang vertically on twigs inside dense shrubbery.
Hydrobasileus croceus | Description and habitat
It is a large dragonfly with its head rather broad from side to side and eyes are moderately separated with emerald green colour. Its thorax is black with three oblique bright yellow stripes. Its wings are transparent with dark brown apices and black pterostigma. Abdomen is black with yellow markings. The colour and markings of the female is very similar to the male. It is commonly found in mountains in the Western Ghats, soaring in high altitudes. The species is named after .
Chlorogomphus campioni | Description and habitat
Males position themselves here in an attempt to copulate with already-mated females through seduction or force. A study conducted by Chuchill-Stanland et al., showed that a male's size can dictate their mating success rate. Researchers found that flies weighing approximately 8–9 mg had optimum mating success while smaller flies (i.e. <6 mg) had significantly less mating success. Furthermore, when males were equal or larger in size, mating frequency was equal and events such as eclosion, flying, and mating speed were positively correlated with pupal size. During the courtship phase, a series of signals are exchanged between the male and the female.
Ceratitis capitata | Males
Members of this genus are medium-sized dragonflies with dark bodies and a metallic green lustre. The eyes are brilliant green, and many species have dull to bright yellow markings on the thorax and/or abdomen. The abdomens of males are distinctive, with the first two segments bulbous-shaped, the third constricted, and the rest of the abdomen club-shaped with a straight ending. Females have abdomens with straighter sides. Identifying these dragonflies to species can be difficult. The cerci of males, on the tip of the abdomen, are distinctively shaped in each species, as are the subgenital plates on female abdomens. In some species, the subgenital plate is large and projecting, and is used as a "pseudo-ovipositor" for inserting eggs into a substrate.
Somatochlora | Description
In most large species of dragonflies, the wings of females are shorter and broader than those of males. The legs are rarely used for walking, but are used to catch and hold prey, for perching, and for climbing on plants. Each has two short basal joints, two long joints, and a three-jointed foot, armed with a pair of claws. The long leg joints bear rows of spines, and in males, one row of spines on each front leg is modified to form an "eyebrush", for cleaning the surface of the compound eye.
Dragonfly | General description
"Chalcostephia flavifrons" is a fairly small species of dragonfly, with a hind-wing length of . The mature adult male is a bluish-grey colour and pruinose (covered with a dusting of wax particles on top of the cuticle). The adult female and the newly emerged male are dark with bold yellow banding. Both males and females can be distinguished from other similar species by their yellow face contrasting with the flattened, metallic green frons (front of the head). The membranous, veined wings are transparent except for the pterostigmata, a small group of thickened cells at the leading edge of the wing-tips, which have pale centres and dark edges.
Chalcostephia | Description
Males usually recognize female snails by cues in their mucous trails. However, females try to mask their gender by altering these cues. In damselflies, females also try to mask their gender by mimicking male colors, which make them less attractive to males.
Sexual coercion among animals | Male avoidance/habitat change
A population can consist of several hundred insects. "L. sponsa" mate in the usual dragonfly manner and will form tandem pairs away from water. Copulation lasts from 30–60 minutes and after mating they stay paired for egg-laying. The female usually lays eggs in submerged vegetation and whilst egg-laying the female can remain submerged for 30 min. The female pierces the tissue of aquatic plants and inserts her eggs. Occasionally females lay their eggs in vegetation above the water surface in places that will become submerged when the water level rises. The eggs start to develop and will continue to develop for the next few weeks.
Lestes sponsa | Behaviour
Insects display a wide variety of sexual dimorphism between taxa including size, ornamentation and coloration. The female-biased sexual size dimorphism observed in many taxa evolved despite intense male-male competition for mates. In "Osmia rufa", for example, the female is larger/broader than males, with males being 8–10 mm in size and females being 10–12 mm in size. In the hackberry emperor females are similarly larger than males. The reason for the sexual dimorphism is due to provision size mass, in which females consume more pollen than males. In some species, there is evidence of male dimorphism, but it appears to be for the purpose of distinctions of roles.
Sexual dimorphism | Insects
It is a small dragonfly with dark reddish-brown eyes. Its thorax is dark chocolate-brown on dorsum and humeral region, paling on sides. Wings are transparent, tinted with deep golden-amber at base. Abdomen and anal appendages are bright red. Female is similar to the male; but greenish-yellow in colors. It breeds in weedy ponds and lakes.
Aethriamanta brevipennis | Description and habitat
It is a crepuscular dragonfly, active in the dusk. This species can be easily distinguished by the multicolored upper surface of frons and by the shape and relative lengths of the anal appendages. Its labium and labrum are golden-yellow and face and frons are greenish yellow and eyes are green, bluish when aged. Its thorax is pale olivaceous brown with dark brown sutures. Its segment two of the abdomen is turquoise blue. Segment three has a large blue patch at each side. Segments 4 to 9 have an irregular black middorsal stripe. Segment 10 is black.
Anax parthenope | Description
"Orthetrum coerulescens" can reach a body length of . These dragonflies have a thorax with pale yellow ante-humeral stripes. In the males the color of these stripes fades with age. The abdomen is rather slim and shows an evident dorsal keel. Males have blue-grey eyes and a blue pruinescence on the abdomen, developed with age. Young males are yellow-brown. On the contrary some (androchrome) females at the end of the reproductive cycle assume the bluish color of the male. In the female the abdomen is yellowish-brown, with a thin median black line and small transverse lines to the connections of the various segments.
Keeled skimmer | Description
It is a medium-sized rusty dragonfly with transparent wing tips. Male has a reddish-brown face with eyes which are dark reddish brown above, golden brown below. Thorax, abdomen and legs are reddish brown. Wings are dark reddish brown with an irregular triangular transparent area at the tip of the wing. The wing spots are dark reddish brown. Many forms of females are found. Color of head, thorax and abdomen paler than males or rusty brown. Wings are clear amber yellow with a dark ray extending to the tip in fore wing. Many of them have an irregular triangular transparent area at the tip of the wing.
Neurothemis fulvia | Description
Dragonflies (suborder Anisoptera) are heavy-bodied, strong-flying insects that hold their wings horizontally both in flight and at rest. By contrast, damselflies (suborder Zygoptera) have slender bodies and fly more weakly; most species fold their wings over the abdomen when stationary, and the eyes are well separated on the sides of the head. An adult dragonfly has three distinct segments, the head, thorax, and abdomen as in all insects. It has a chitinous exoskeleton of hard plates held together with flexible membranes. The head is large with very short antennae. It is dominated by the two compound eyes, which cover most of its surface.
Dragonfly | General description
"D. melanogaster" males exhibit a strong reproductive learning curve. That is, with sexual experience, these flies tend to modify their future mating behavior in multiple ways. These changes include increased selectivity for courting only intraspecifically, as well as decreased courtship times. Sexually naïve "D. melanogaster" males are known to spend significant time courting interspecifically, such as with "D. simulans" flies. Naïve "D. melanogaster" will also attempt to court females that are not yet sexually mature, and other males. "D. melanogaster" males show little to no preference for "D. melanogaster" females over females of other species or even other male flies.
Drosophila melanogaster | Males
Females are usually about 28 millimeters in length, while males are usually about 25 millimeters. Females have short antennae, while males have long and red antennae. Females are bulkier than males. Eight segments can be counted on the underside of the abdomen of a male and six on that of the female. Females have two dots on their abdomens as adults, while males, whose abdomens are thin and covered completely by their wings when looked at from above, appear to have none.
Pseudoharpax virescens | Sexual dimorphism
Dragonfly wings behave highly dynamically during flight, flexing and twisting during each beat. Among the variables are wing curvature, length and speed of stroke, angle of attack, forward/back position of wing, and phase relative to the other wings.
Dragonfly | Flight
A 2015 study showed that high-temperature incubation of eggs transforms genetically male individuals into functional females. Normally their sex is determined genetically. Males have ZZ sex chromosomes, females ZW. However, when their eggs are incubated at temperatures above 32 °C (90 °F) some genetic males are born female. These females are fertile, sometimes producing more eggs than the ZW females. As juveniles, the sex reversed ZZ females resemble ZZ males with respect to relative tail length and boldness. However, as adults sex-reversed ZZ females lack the larger head and greater bite force of ZZ males and more closely resemble ZW females.
Central bearded dragon | Thermally induced sex reversal
Males fly more often than females, due to the release of pheromones produced by the females. Females limit flying to make their pheromone trail more apparent to the males for mating. Copulation between mating pairs can last up to 16 hours, and the pair stay together until throughout the attraction period to ensure the female mates with one male.
Dicosmoecus gilvipes | Flight & Reproduction
It is a medium sized dragonfly with yellowish white face and blue eyes. Its thorax is yellowish green with some brown stripes. Its wings are transparent, including the base. Its abdomen is pruinosed with azure blue up to the last segments. In old adults, thorax will also get pruinosed, obscuring whole the marks. Females and young males are yellowish green. They breed in marshes and swampy areas in the plains.
Orthetrum luzonicum | Description and habitat
It is medium size damselfly with black-capped brown eyes. Its hindwings are about 19–20 mm and the abdomen about 30 mm. The male of this damselfly is mostly black with red and yellow stripes on its thorax and small yellow spots on the abdomen. The pterostigma or the wing spot is diamond-shaped and is dark brown in colour. Abdomen is black with segments 3 to 6 have small base-dorsal yellow spots. Remaining segments are unmarked. The female is similarly marked to the male; but the thoracic stripes are paler and more yellowish. They are commonly found along the banks of large ponds and rivers, usually sitting among emergent water plants.
Prodasineura verticalis | Description and habitat
It is a medium sized dragonfly with bottle-green eyes. Its thorax is dark metallic-blue, marked with citron-yellow. There is a narrow mid-dorsal carina, a humeral spot and a narrow stripe on mesepimeron. Abdomen is black, marked with citron-yellow. Segment 1 has a triangular spot on mid-dorsum. Ssegment 2 has a small diamond-shaped spot on mid-dorsum. Segment 3 has its base dorsally and sub-dorsally narrow yellow and a stellate spot on mid-dorsum. Segments 4 to 9 are similar to 3; but the lateral spots much smaller. Segment 10 is entirely black. Anal appendages are black. Female is similar to the male.
Onychothemis testacea | Description
It is a small dragonfly with brown-capped yellowish-green eyes. Its thorax is olivaceous-brown, marked with a reddish-brown humeral stripe and two brownish stripes on each side. Wings are transparent; but with a broad bright orange fascia extending from base to within 2 to 3 cells of reddish pterostigma. Abdomen is ochreous-red, marked with dorsal and sub-dorsal brown stripes. Anal appendages are in reddish-brown. Female is similar to the male; but in pale yellowish-green color. Wings are transparent, tinted with yellow at extreme base;, but the bright orange fascia seen in the male absent. It breeds in weedy ponds, lakes, and slowly moving streams; especially in sluggish waters.
Brachythemis contaminata | Description and habitat
"T. angusticollis" flies demonstrated sexual dimorphism with males often presenting as larger and with more exaggerated traits than females. Males, in particular, tend to have elongated heads, antennae, and legs than their female counterparts. The extent of the dimorphism is dependent on genetics as well as parental diet as described below. Such dimorphism may have developed in males as the exaggerated features are those that males would rely on in male to male combat.
Telostylinus angusticollis | Sexual dimorphism
This dragonfly is found at shaded pools, such as those found in gallery forest.
Tetrathemis polleni | Habitat
"Hemigomphus comitatus" is a small dragonfly with black and yellow markings. Its wingspan is 50-55mm and overall length is 40-45mm. The eyes of the adult are green and do not meet at the top of the head. The head of the female has a spine from the occiput just behind the eyes. The synthorax is strongly marked with black and yellow stripes, with the humeral stripe usually being continuous. A black mark along the suture of the synthorax is usually broken above and below the metastigma. The abdomen is black with prominent yellow bands, the appendages of the male are yellow and curve inwards at the tip.
Hemigomphus comitatus | Description
It breeds in streams in forest or at its margins. This is a very fast flying dragonfly of forested streams. Males usually perch on dry twigs and other similar vantage points over streams and aggressively chase other dragonflies entering their territory.
Onychothemis testacea | Habitat