Temperature Tolerance and Predatory Strategy of Pit-Building Ant-Lion Larvae (Neuroptera: Myrmeleontidae)

Abstract

This study focuses on the nocturnal and diurnal temperature relations inside and around the pits of Myrmeleon bore pit-building ant-lion larvae living in unsheltered microhabitat and Euroleon nostras living in sheltered microhabitat. The larvae's potential hunting activity and prey handling phase of predation in relation to the temperature conditions were observed. Due to the structure of pitfalls and the thermal layers above and under the sand surface, the larvae must suffer less temperature fluctuation during the day than their environment. The role of the pitfall seems to be just as important in prey capturing as in temperature tolerance. This function of pits especially prevails in unsheltered microhabitats. In unsheltered microhabitats temperature influences the potential predator activity as well as the distribution of prey handling phase of predation in time. The potential hunting activity of larvae is not influenced by temperature in sheltered microhabitats, where their prey handling phase of predation depends mainly on the activity of prey species. It takes one year for both species to develop, but underdeveloped individuals of two-year life cycle can also be found. During the observation period, the chances of development for normally developed larvae living in unsheltered microhabitats proved far better than the chances for underdeveloped larvae due to the temperature. During their evolution, pit-building ant-lion larvae have strongly adapted themselves to extreme environmental factors physiologically and behaviourally as well.

Heat wave effects on the behavior and life-history traits of sedentary antlions

“…Our study species were previously demonstrated to experience differing levels of temperature fluctuations in nature, that is, relatively higher in M. bore and lower in E. nostras ( Lackinger 1973 ; Abraham 2003 ). Additionally, both of these species show an increase in some activity parameters at 35 °C when compared with lower temperatures ( Klokočovnik et al 2016 ; Antoł et al 2018 ).…”

Preference of antlion and wormlion larvae (Neuroptera: Myrmeleontidae; Diptera: Vermileonidae) for substrates according to substrate particle sizes

“…Microclimate can play an important role in pit-building decisions, e.g. shade (Topoff, 1977;Scharf et al, 2008c), photoperiod (Scharf et al, 2008c), soil temperature (Geiler, 1966;Marsh, 1987;Ábrahám, 2003), rain and soil moisture (Gotelli, 1993;Morrison, 2004).…”

Thermal dependence of trap building in predatory antlion larvae (Neuroptera: Myrmeleontidae)

“…In addition, building larger cone-shaped traps in response to stronger solar radiation might signify thermoregulatory behavior. Indeed, the base of pitfall traps has been shown to provide larvae with lower mean temperatures and reduced thermal fluctuations compared to the upper surface of the sand, where larvae establish their traps (Green 1955 ; Marsh 1987 ; Abraham 2003 ). In our experiment, we heated a layer of sand from the bottom, which means that by choosing to build a larger trap, a larva was closer to a heat source than a larva building a smaller trap.…”

“…To address the effects of the thermal environment on antlion hunting, we conducted a laboratory experiment on trap building in Myrmeleon bore larvae along an ecologically relevant thermal gradient. Although M. bore has been used to study antlion feeding biology and trap establishment (Matsura 1986 , 1987 ; Matsura and Takano 1989 ; Abraham 2003 ; Matsura et al 2005 ), thermal biology has never been studied in this species. We tested two competing hypotheses.…”