Zygonyx torridus inhabits waterfalls, rapids and riffle sections. Males patrol over these sites. After copulation the partners perform an extensive search while flying in tandem over a wide range. Behavioural studies in Mauritius 1997 and 2014 showed that there is considerable plasticity in oviposition behaviour. Three main modes could be distinguished: (A) egg-laying in tandem…
A new species of the endemic New Guinean genus Lanthanusa is described from the Trauna River Valley in Western Highlands Province, Papua New Guinea. Characters of the male are illustrated and affinities of the new species are discussed. Some characters of the type species of Lanthanusa, L. cyclopica, are reassessed and a revised key to…
Food intake rate and diet composition have a high impact on all organisms and affect individual fitness, fecundity and mortality. Specimens in enclosures have to be fed in an adequate way and with minimum stress for the specimens. Adult dragonflies are flying hunters. In enclosures, they are usually fed by adding different kinds of adult…
The levis and ferruginea groups of Orthemis are redefined. Six new species of Orthemis are described: O. aciculata sp. nov. (♂ holotype: Surinam, Para Dist., road near forest, Zanderij I (5°32′ N, 55°10′ W), 17 January 1957, leg. J. Belle [RMNH]), O. celata sp. nov. (♂ holotype: Brazil, Pará State, Rio Gurupí, Canindé (0°30′57′ ′…
Lanthanusa bilineata, a new libellulid from the mountains of central New Guinea (holotype: Mekil Research Station (04°48′ S, 141°39′ E), leg. 1 September 2004, dep. at RMNH, Leiden), is described. The new species combines characteristics previously used to distinguish between Huonia and Lanthanusa with wing venation characteristic of the genus Huonia and accessory genitalia characteristic…
Clutch size is an important fitness component often quantified artificially by inducing oviposition in libellulid females. Female behavior and egg production of the yellow-veined skimmer, Orthetrum nitidinerve, were studied in northeast Algeria during its reproductive season. Data on reproductive behavior and biology of this Mediterranean endemic species has not been published previously. Males guarded territories…
Oviposition behaviour by Sympetrum frequens, a species endemic to Japan, has been observed throughout its entire breeding season, which extended for about one month after the harvest of rice. Approximately 50% of oviposition events occurred during the first week of the reproduction period. Sunny oviposition sites were preferentially selected by ovipositing pairs. The starting time…
Behaviour of dragonflies was observed during the partial solar eclipse in Saitama, Japan, on 22 July 2009. The solar eclipse started at 09:54 h, reached its maximum magnitude of 74.9% at 11:12 h, and ended at 12:29 h. Light intensity at the peak of the eclipse was 1005 lx, a reduction by 28.2% of that…
Oligoclada mortis sp. nov. (holotype male deposited in MZSP: Brazil, Rondônia State, Porto Velho municipality, “T[ransect] 5-21, seg[ment]12” (09°35′19′′S, 65°02′50′′W, 106 m asl, 13 v 2010, leg. Nogueira & Mendes) is described and illustrated based on two males. The new species fits within Borror’s Group III, differing from all other described species in the genus by…
In libellulids, mature oocyte size varies within and between individual ovaries. The regulating mechanism is not yet understood. Variations in the contents of the follicle cells, and thereby their ability to secrete material into the oocyte, might explain some of the observed differences in oocyte size. We therefore investigated the follicle cell surface, the interstitial…