Diel pattern of activity, mating, and flight behaviour in Onychogomphus uncatus (Odonata: Gomphidae)

The behaviour of Onychogomphus uncatus, including flight and mating activity, was studied at a fast-flowing irrigation canal. During the day, males perched in sections of the canal with a strong current and a turbulent water surface. During short flights, interactions with other con-specific and hetero-specific males occurred, particularly with Orthetrum coerulescens. Under conditions of high…

Reproductive behaviour of Odonata: the history of a mystery

The main, externally visible components of odonate reproductive behaviour were known from published accounts for about 300 years before sperm displacement during copulation was first described. The latter discovery, revealed by Jonathan Waage in 1979, revolutionised the interpretation of odonate reproductive behaviour, allowing it for the first time to be interpreted convincingly in the context…

A synopsis of the genus Triacanthagyna (Odonata: Aeshnidae)

This synopsis of adult Triacanthagyna includes the revalidation of two species thought to be synonyms (T. nympha and T. obscuripennis), the description of a new species (T. williamsoni; type locality: Peru, Tingo María), keys to both sexes, illustrations of diagnostic characters, and distribution maps of all species. A phylogenetic assessment of the nine species is…

Nested-subset structure of larval odonate assemblages in the Enoree River basin, USA

Communities have a nested-subset structure if the species found in species-poor assemblages are also found in progressively more species-rich assemblages. This nested-subset structure can be caused by differential colonization rates among species, differential extinction rates among species, or nested niche space. In this study, the assemblages of larval odonates in the Enoree River of South…

Abundance and vertical distribution of a bromeliad-dwelling zygopteran larva, Mecistogaster modesta, in a Costa Rican rainforest (Odonata: Pseudostigmatidae)

We compared the larval abundance of Mecistogaster modesta between bromeliads at ground level and canopy level in a primary tropical wet forest. Zygopteran abundance correlated strongly with bromeliad diameter at both levels. Although the per-bromeliad zygopteran abundance did not differ between vertical levels, M. modesta showed a strong vertical distribution in abundance owing to the…

Stadia and growth ratios of Odonata: a review

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…