Egg Development, Growth, and Metabolism of Sigara Alternata (Say) (Hemiptera: Corixidae) in Fluctuating Thermal Environments

Abstract

Egg development and growth of Sigara alternata in southeastern Pennsylvania, USA were evaluated in six fluctuating temperature regimes with daily maxima ranging from 12.0° to 21. 5°C. Developmental rate was positively correlated with increased magnitude of the diel temperature pulse. Developmental acceleration was most apparent for environments pulsing beyond 15.0°C for both stages. Oviposition rates were studied at natural temperatures during the initial days of reproduction. Egg deposition was sporadic but highly correlated with maximum diel temperatures. A critical temperature region of 11.0—12.5°C was observed for initiation and maintenance of egg laying. Metabolic rates were measured using a different respirometer. The thermal response of metabolism varied with animal soze and the range of test temperatures. The energy demand per uniy weight of tissue was inversely related to body size at all temperatures. Adult population metabolism decreased exponentially during the peak reproductive period due to high mortality. Energy budgets were determined for nymphal development in all thermal regimes. Net growth efficiencies and production/respiration ratios for Sigara alternata ranged from 49.7—73.4% and 0.9—2.7 respectively. Assimilation rates increased with rinsing temperatures and varied between 1.05 and 3.52 J.mg—1.day—1 [=0.25 —0.84 cal.mg—1.day—1]. Net growth efficiencies tended to decrease with increased temperatures due to higher maintenance costs. The significance of fluctuating temperatures to the bioenergetics, developmental dynamics, and ecology are discussed .

Hatching phenology and voltinism of Heterocypris barbara (Crustacea: Ostracoda) from Lampedusa (Sicily, Italy)

“…Moreover, even if LC was not tested at FT, conductivity did not affect either hatching time of resting eggs or physiological time at completion of life cycle in generation I. This result confirms that natural thermal fluctuation, from day to night and from colder to wormer months, influence developing of invertebrates (Sweeney and Schnack, 1977;Ikeda, 1992;Montagnes and Weisse, 2000;Putnam et al 2010), but an acceleration of growth rate in fluctuating temperatures was observed in Daphnia (Orcutt and Porter, 1983) and rotifers (Halbach, 1973). Moderate thermal fluctuations may be associated with faster growth while retardation of development was described in fluctuating regimes encompassing extreme temperatures (Worner, 1992;Thorp and Wineriter, 1981).…”

“…To mimic the natural thermal fluctuations that affect invertebrate development (Hubbs, 1964;Sweeney and Schnack, 1977;Scholnick, 1995), two more microcosms were maintained on the laboratory windowsill from February to May. Throughout the experimental period, in our laboratory (45° latitude N), temperature and photoperiod were similar to the early spring breeding hydroperiod in Lampedusa.…”

Water Quality and Aquatic Insects Study at the Lower Kinabatangan River Catchment, Sabah: In Response to Weak La Niña Event

“…The correlation is possibly caused by preys (food) that are more abundant at locations with increased nutrient concentrations (Maul et al 2004). This is supported by previous studies which demonstrated that Corixidae feed on stream bottom organic matter containing algae, diatoms (Alahmed et al 2009;Cummins 1973;Sweeney & Schnack 1977) and Gerridae feed on detritivores and small arthropods at or near water surface that could be more abundant related to increasing nutrient concentrations (Cummins 1973;Jardine et al 2008;Sih & Watters 2005). Fernandez and Lopez Ruf (2005) reported that Gerridae was found in streams that subjected to agricultural and cattle-rearing activities in La Plata estuary, Argentina.…”

Climate change and freshwater ecosystems: impacts across multiple levels of organization

“…growth and metabolism under warming; Sweeney & Schanck 1977) or focal species populations (e.g. polewards or altitudinal range shifts; Babaluk et al 2000).…”