![]() ![]() This example is one of the simplest confirmed cases of NFDS maintaining genetic polymorphisms in nature. The demographic properties of the observed dynamics agree well with those of our model. Morph frequencies in a small population undergo large oscillations whereas those in a large population do small oscillations. The long-term field surveys show that the morph frequencies oscillate with a period of two generations. Thus the conditions necessary for NFDS are satisfied. Fitnesses of the two morphs are an inverse function of its own frequency in a population, and are about equal when their frequencies are similar. Red eyes and its bright abdomen spot is lower down on segment 9-10. Specifically, we (1) test fitness responses to morph frequencies, (2) built a simple population genetic model, and (3) compare the observed and predicted morph-frequency dynamics. A widespread and extremely common species, also called the Common Bluetail. Length: 30 to 34mm Flight season: Late April to September, longer flight period further south. e-mail: email protected (To whom correspondence should be sent. Zaika Addresses of the authors Institute of Cytology and Genetics SB RAS, Acad. Here we investigate NFDS in wild populations of the dimorphic damselfly Ischnura senegalensis, in which females occur as andromorphs and gynomorphs. Ischnura elegans, (Vander Linden, 1820) Blue-tailed Damselfly. IDF-Report 5 (2003): 1-44 1 Odonatological expeditions to the Tyva Republic (Tuva) 2000-2002 O. Some of them are very complicated, although strongly supportive of the NFDS. Only an inch in length, the male is nonetheless easily recognized by the four tiny blue dots. Common bluetail (Ischnura heterosticta) Mr Haywood prefers to call it. Recently many prospective cases of polymorphisms by NFDS have been reported. Pacific Forktail is a common and widespread little damselfly. because both the male and female greenling look like a female bluetail, for example.'. A recent study has shown that they can compensate for a whole wing loss and even successfully maneuver and catch prey.Negative frequency-dependent selection (NFDS) is one of the most powerful selective forces maintaining genetic polymorphisms in nature. The females always lay their eggs on the floating parts of the plants without any involvement of the male.īlue-tailed Damselflies are superb fliers and can alter each of their four wing's kinematics in order to maneuver. Damselfly nymphs are aquatic, and prey on small aquatic insects or other aquatic larvae.Ī male can try to interfere with a mating pair, by attaching itself to the mating male. The adult damselflies prey on small flying insects, caught using their legs like a basket to scoop the prey up while flying, or insects taken from leaves. They thrive in disturbed and open habitats and can be seen in almost all the ponds in our parks and gardens. Sometimes, females can look similar to males too Habitat and Behaviour. Females come in a variety of colours, but the most common is a golden orange thorax. Biology and behavior Īdults fly from April to September to early October. Males can be easily identified by their green thorax and blue abdomen tip. Ischnura heterosticta, one of at least two species with the common name common bluetail, is a common Australian damselfly of the family Coenagrionidae. Mature females may be blue like the male, form typica olive green thorax and brown spot, form infuscans or pale brown thorax and brown spot, form infusca-obseleta. The colour darkens as the damselfly ages. Juveniles may be salmon pink, form rufescens violet, form violacea and a pale green form. įemale blue-tailed Damselflies come in a variety of colour forms. ![]() The thorax of juvenile males has a green tinge. At rest, the wings of most damselfly species are held back together, unlike dragonflies, which rest with their wings out flat. The species can reach a length of 32 to 35 mm (1.3 to 1.4 in). A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W. ![]() Segment eight, however, is entirely pale blue. Enallagma cyathigerum ( common blue damselfly, common bluet, or northern bluet) is a species found mainly between latitudes 40N and 72N 1 It is widely distributed in the Palearctic, and the Nearctic species Enallagma annexum was at one time considered to be synonymous with it. They have a largely black abdomen with very narrow pale markings where each segment joins the next. There is a bi-coloured pterostigma on the front wings. The most common female morph is then expected to be disproportionally harassed. Adult male blue-tailed damselflies have a head and thorax patterned with blue and black. Blue-tailed Damselfly: colour forms Blue-tailed Damselfly: male vs female Bluets / Blue-striped Damselfies. Of the approximately 75 species in the genus Ischnura, c.a. Hindwings reach alength of 14–20 millimetres (0.55–0.79 in). Ischnura elegans can reach a body length of 27–35 millimetres (1.1–1.4 in) and a wingspan of about 35 millimetres (1.4 in). ![]()
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