The effect of fasting and body reserves on cold tolerance in 2 pit-building insect predators

Abstract

Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional similarities in their natural history and ecology, and thus, these 2 species encounter similar abiotic stress (such as periodic starvation) in their natural habitat. Here, we measured the cold tolerance of the 2 species and examined whether recent feeding or food deprivation, as well as body composition (body mass and lipid content) and condition (quantified as mass-to-size residuals) affect their cold tolerance. In contrast to other insects, in which food deprivation either enhanced or impaired cold tolerance, prolonged fasting had no effect on the cold tolerance of either species, which had similar cold tolerance. The 2 species differed, however, in how cold tolerance related to body mass and lipid content: although body mass was positively correlated with the wormlion cold tolerance, lipid content was a more reliable predictor of cold tolerance in the antlions. Cold tolerance also underwent greater change with ontogeny in wormlions than in antlions. We discuss possible reasons for this lack of effect of food deprivation on both species’ cold tolerance, such as their high starvation tolerance (being sit-and-wait predators).

Superior basal and plastic thermal responses to environmental heterogeneity in invasive exotic stemborer Chilo partellus Swinhoe over indigenous Busseola fusca (Fuller) and Sesamia calamistis Hampson

“…Despite the importance of invasive lepidopteran stemborers to African agriculture, to our knowledge, there are no studies available investigating their physiological responses to multiple stressors. Related studies specifically focus on noncrop pest insect model organisms (Sinclair et al ., ; Nyamukondiwa et al ., ; Bubliy et al ., ; Chidawanyika et al ., ; Scharf et al ., ). Furthermore, most studies focus on the adult life‐stage because it is responsible for reproduction, host selection and dispersal, and perhaps because it is more conspicuous (Klockmann et al ., ).…”

Oxidative stress delays development and alters gene function in the agricultural pest moth,Helicoverpa armigera

“…In the former study, the intriguing hypothesis of hormesis was raised to explain the fact that a compound that has an inhibitory or toxic effect at high doses can actually be beneficial at low doses (sensu Mattson, 2008). In fact, there is substantial research regarding hormesis due to the impacts of environmental stress on aging and longevity in invertebrate species (Le Bourg, 2009;Hunt et al, 2011;Scharf et al, 2017;Gilad et al, 2018;Mir & Qamar, 2018), including Helicoverpa Celorio-Mancera et al, 2011;Gulzar & Wright, 2015). In our case chronic oxidative stress extended the larval period in H. armigera, which is the developmental stage that causes the most damage to crops.…”

<b>Cannibalism among <i>Myrmeleon brasiliensis</i> larvae (Návas, 1914) (Neuroptera, Myrmeleontidae)

“…Antlion larvae of the genus Myrmeleon (Neuroptera, Myrmeleontidae) are typical 'sit-andwait' predators. The larvae build funnel-shaped traps in sandy soil (Farji-Brener, 2003;Hauber, 1999;Scharf, Daniel, Macmillan, & Katz, 2016). Experiments in both the natural environment and laboratory report the occurrence of cannibalism among Myrmeleon spp.…”