The large Neotropical zygopterans Megaloprepus caerulatus, Mecistogaster linearis and M. ornata (Pesudostigmatidae) were surveyed during five years, and striking differences in their reproduction patterns were shown: (1) At two study sites in seasonal, tropical semi-dry forests in Pacific Costa Rica, adult M. ornata could be observed throughout the year, occasionally during the dry season up…
Quantitative data are essential for many aspects of ecological research. Several methods exist to quantify odonate abundance, but complications may arise when abundances in different habitats need to be compared. In this study, I explored a technique that can overcome the variable detectability of odonates in habitats with different visibility. Distance sampling is briefly introduced…
During the 2003/2004 summer flying season, upright emergence of a male Petalura gigantea was observed and photographed in the Blue Mountains of New South Wales during an extensive survey for the species. This observation differed from the only previous illustration of a hanging back emergence style, and is compared with observations of emergence style for…
We compiled data on the occurrence and frequency of distinct female variants among Holarctic Odonata and interpreted the data in light of harassment-based hypotheses. The major source of male confusion for male mimicry hypotheses is predicted to be signal similarity between andromorphs and male distractors; for the learned mate recognition hypothesis (LMR), it is predicted…
In the premontane rain forests of northwest Costa Rica, patches of secondary forest can contain high densities of large Vriesea spp. bromeliads. Such patches contain an average of 6,470 ± 1,080 (s.e.) larvae ha-1 of the bromeliad-dwelling pseudostigmatid, Mecistogaster modesta, ca 3 6× higher than larval densities that we previously reported for adjacent primary forest.
The region covered is briefly defined and characterized as relatively little disturbed. A survey of relevant odonatological literature, including local Red Lists, is given, along with current scientific activity. Sixteen species are indicated, which deserve special attention, one of them, Ischnura aralensis, being the only strict endemic in the region. Some isolated populations deserving protection…
The Philippine odonate fauna is characterized by a high percentage of endemic species, especially in Zygoptera, most of which have a very limited range. Due to the continuing loss of forests and other habitat destruction, a majority of the 300 plus known species could be red-listed, but only a few critical species are evaluated here.
Ten species of Hawaiian Odonata are considered to be currently at risk, all of them zygopterans belonging to the endemic genus Megalagrion. These species and their proposed status are as follows: M. jugorum, endemic to Maui and Lanai [CR, possibly EX]; M. leptodemas, endemic to Oahu [CR]; M. molokaiense, endemic to Molokai [CE, possibly EX];…
A brief Odonata survey in southern Florida, USA, in January 2000 resulted in the discovery of two new species, Chrysobasis lucifer and Nehalennia minuta, for the USA and established populations of two other species, Tholymis citrina and Tramea calverti, that had been considered vagrants. Flight seasons of six additional species were extended. These records are…
A survey of 32 lakes for dragonfly larvae, aquatic plants and forestry regime in the surrounding boreal forests was performed. The highest diversity was found in undisturbed forests. Lakes rich in aquatic plants were shown also to be rich in dragonflies. A rich plant community is proposed to provide a wider range of microhabitats thereby…