Flight initiation distance in dragonflies is species-specific, positively related to starting distance and sometimes body length

Predator escape behaviour is a critical component of dragonfly life history. Flight initiation distance is the distance at which escape commences, and is well studied in vertebrates, barely studied in invertebrates, and entirely unstudied in dragonflies. Here we test four principles regarding flight initiation distance as derived from studies of vertebrates to examine if they…

The factors influencing the length of the terrestrial period in the final instar larvae of Epiophlebia superstes (Selys, 1889) (Anisozygoptera: Epiophlebiidae)

The terrestrial period before adult eclosion of the final instar larvae of Epiophlebia superstes was studied during spring 2008 to 2012, at a mountain stream in Nurukawa, Aomori prefecture, northern Japan. The average terrestrial period of larvae that left the water during early, middle and late April, estimated by mark-release-recapture and caging methods, was 45.3…

Useful biometric variables in Iberian exuviae of Boyeria irene (Fonscolombe, 1838) (Odonata: Aeshnidae)

In species of similar shape and size, biometric analyses make it possible to establish differences. Within one species, biometrics can help researchers to detect differences between populations and analyze their adaptations to environmental conditions. Until now little was known about the biometrics of the Iberian populations of Boyeria irene (Odonata: Aeshnidae), a large species living mainly in southern Europe.