Water Strider Species Research Articles

The effects of temperature on growth and development of water strider species (Heteroptera: Gerridae) of central British Columbia and implications for species packing

The duration of life-cycle stages and the effects of temperature on development were assessed with laboratory rearing studies for six species of water striders which occur sympatrically in British Columbia. Larval production and development are strongly temperature dependent in all species studied. Temperature thresholds for development differ, both among species and often among stages of particular species. Instars of Gerris species showed distinct optimum temperatures for laboratory survival which varied with developmental threshold. Low thresholds calculated for G. pingreensis lead to significant growth advantages for this species during early spring. Threshold differences between species and instars appear to be adaptations to seasonal temperature regimes and to usual habitats occupied by gerrids. These relationships lead to temporal separation of species and help explain the patterns of habitat occupation observed in the study area.

HABITATS, LIFE CYCLES, AND GUILD STRUCTURE AMONG WATER STRIDERS (HETEROPTERA: GERRIDAE) ON THE FRASER PLATEAU OF BRITISH COLUMBIA

AbstractHabitats and life cycles of five species of water striders were compared in south-central British Columbia. Three species of Gerris were bivoltine; both Limnoporus species were univoltine. Generation timing varied markedly among lakes and periods of maximum abundance for all species overlapped. Each species showed distinct association with a single type of habitat defined by vegetation structure. These associations separate most species among lakes and suggest that habitat is the most important resource axis for ecological separation of gerrid species on the Fraser Plateau.

A heavy infestation of gerrids (Hemiptera–Heteroptera) by water mites (Acarina–Limnocharidae)

Two species of water striders, Gerris comatus and G. buenoi, were found heavily infested with water mites (Limnochares sp.) in Sunfish Lake, Waterloo, Ontario. All the gerrids collected from 5 to 26 July, 1969, were infested.The intensity of infestation varied from 2 to 205 (mean 40.5) in 42 host specimens, both instars and adults. Accelerated mortality of the host was probably due to the mite infestation. The spatial distribution of mites on the host and the rarity of gerrid infestation reported in the literature are discussed.

Studies on Some Inland Waters of the Galapogos

Arcturus Lake is a stratified hypersaline lake occupying a caldera near the center of Genovesa Island. It is about 500 m in diameter and has a maximum depth of 30 m. The lake is frequented by large numbers of seabirds and is an outstanding example of guanotrophy. Organic production in the epilimnion was great, and the hypolimnion was anoxic at the time of these studies. The lake is probably stratified during the entire year. There appear to be no fishes in the lake. The invertebrate fauna is dominated by corixids and tanaid shrimps. Tagus Crater Lake on Isabele Island, occupies a crater about 100 m from Tagus Cove. It is about 400 m in diameter and 10 m deep over most of the basin. The lake is saturated salt brine with a bottom of rock salt. The fauna is dominated by corixids and anostracan shrimps. Of three small ponds at Noah's Coves. Isabele, one has low salinity from top to bottom, whereas the other two are markedly stratified with regard to salinity. The upper "fresher" water in the stratified ponds is poor in phytoplankton compared to the underlying high—salinity water. Several species of fish, Odonata, corixids, water striders, and crustacean larvae were living in the ponds at the time of these observations.