A two-variable analysis of male and female Cordulegaster boltonii larvae (head width and hindwing sheath length) in specimens from five Iberian populations was carried out with the objective of ascertaining whether these traits differ between populations.
A terminology is presented for structures and events in larval development of Odonata with the aim of bringing terms into conformity with those used for other insect orders in the light of accepted views of homology. The terms ‘exuvia’, ‘larva’, ‘prolarva’ and ‘stadium’ receive special mention. Records of the number of stadia required to complete…
As warm-adapted insects of tropical origin, Odonata cope with cold periods by seasonal regulation and diapause. A model for larval-overwintering species is proposed with three response patterns related to the timing of emergence, which can be predicted from seasonal cues during the last few stadia. For emergence during the present season, there is an often time constrained pre-emergence development, accelerated by long days and higher temperatures.
Larvae were reared at 21.5°C from eggs from southernmost Sweden, and fed ad libitum to emergence in four different photoperiodic treatments, intended to represent increasing levels of time stress: constant LD 16:8, corresponding to late April (or August) conditions, a shift after about two weeks from LD 16:8 to 19.5:4.5, coarsely simulating late spring, constant…
Second and third stadium larvae of Gomphus flavipes have dorsolateral cuticular outgrowths in the form of small basal tubercles bearing fan-shaped setae. These sensilla are aligned in two rows on each side of the thorax and abdomen. European species of Gomphus, Onychogomphus and Ophiogomphus that we examined lack these structures, having instead, at most, short…
Boyeria cretensis belongs to the most threatened European dragonfly species. It is restricted to some isolated permanent streams on the island of Crete. The streams have a pronounced gallery vegetation and are situated in a narrow belt of altitude between 50 and 400 m. We understand very little about the biology of this species so…
Egg size differences might have an important influence on reproductive success because they may lead to different offspring conditions, hatching date or larval size. We presumed that egg size in odonates positively correlates with egg development time, and larger eggs lead to larger larvae. However, we assumed that the size benefit could only be maintained…
A small inconspicuous spine, first detected at the base of the distal-most seta on each labial palpus of early stadia of two species of Enallagma, is reported to occur in final-stadium (F-0) larvae of Palaearctic and Nearctic E. cyathigerum, in F-0 of 31 other Nearctic species of Enallagma and in F-0 of three other coenagrionid…