Constant and shifting photoperiods as seasonal cues during larval development of the univoltine damselfly Lestes sponsa (Odonata: Lestidae)

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…

Behaviour and body size: plasticity and genotypic diversity in larval Ischnura elegans as a response to predators (Odonata: Coenagrionidae)

Phenotypic plasticity represents an adaptive tool in organisms including odonates to cope with heterogeneous environmental conditions. However, while some odonate species can occupy various changing habitats, other species are adapted to a narrow range of environmental conditions. Commonly, behavioural modifications are applied to avoid detection and encounters with predators. But reduced behavioural activity results in…

Critical species of Odonata in southern Africa

Of the 160 species in South Africa, 29 are endemic. Threats to the local odonate fauna have increased in recent years due to the growth of agriculture and impact of invasive alien trees. Currently, 13 species are red-listed as threatened. Among the activities to ameliorate threats, is a massive programme, ‘Working for Water’, to remove…