Temperature and prey capture: opposite relationships in two predator taxa

Abstract

1. All other things equal, predator capture rates are expected to depend on encounter rate with prey, prey escape capability (including prey defences), and on predator agility. Ectotherm predators and their prey both respond to increasing temperature by increased activity, i.e. predators increase their search area and prey may enhance their escape capability. This means that, as temperature changes, the ability of a predator to catch prey will decrease, increase, or remain unchanged depending on the relative effect of temperature on predator and prey. Their responses may further be differentially moulded by light conditions depending on whether the predator is diurnally or nocturnally active. It was hypothesised that flying Diptera are vulnerable to carabid beetles only at low temperatures and over the full temperature range for spiders because carabids, in contrast to spiders, are not built to catch swiftly moving prey.2. The first experiment examined the spontaneous locomotor activity of the predators and of fruit flies at different temperatures (5, 10, 15, 20, 25, and 30 °C) and light conditions (light, dark). A second experiment examined the effect of temperature and light on the predation rate of two carabid beetles (Pterostichus versicolor and Calathus fuscipes) and two spiders (Clubiona phragmitis and Pardosa prativaga) using fruit flies (Drosophila melanogaster) as prey.3. All four predators and the fruit fly increased their locomotory activity at higher temperatures. Activity of the carabid beetles peaked at intermediate temperatures; spiders and fruit flies were most active at the highest temperatures. Predation rate of the spiders increased with temperature whereas the beetles caught flies only at low temperatures (5 and 10 °C).4. Diurnal variation in temperature may bring different prey groups within the set of potential prey at different times of the day or at different seasons. The ability of many carabid beetles to forage at low temperatures may have nutritional benefits and increases the diversity of interactions in terrestrial food webs.

The temperature independence of interaction strength in a sit‐and‐wait predator

“…The 'area of capture' parameter a in the functional response (also known as 'attack efficiency' or 'attack rate') typically responds positively to temperature as well, for both parasitoids and consumers, although there is considerable variation in how steeply a increases with temperature and whether it reaches a peak at intermediate temperatures (Ding-Xu et al 2007, Kruse et al 2008, Englund et al 2011. Dell et al (2013) provided a framework for the area of capture parameter that predicts how it responds to temperature.…”

“…This process can be described from the consumer's point of view, such as a functional response, or from the resource point of view, such as changes in population growth rate with and without consumers present. Either way, temperature has the ability to alter interaction strengths because of the kinetic effects of temperature on movement rates, at least for ectotherms (Kruse et al 2008, Englund et al 2011, Dell et al 2013. In colder temperatures, organisms are prone to moving more slowly because metabolic processes inside the organism may be slower (Brown et al 2004, Dell et al 2011.…”

Temporal patterns of nutrition dependence in secondary sexual traits and their varying impacts on male mating success

“…For example, the density of small arthropods, a common prey type for numerous predators, is affected by rainfall (Shultz, Lensing, & Wise, 2006;Staley et al, 2007) and temperature (Bale et al, 2002;PearceHiggins, Dennis, Whittingham, & Yalden, 2010), both of which may change unexpectedly. Additionally, for ectothermic predators, rate (and potentially efficiency) of foraging is positively correlated with temperature (Kruse, Toft, & Sunderland, 2008). Therefore, short-term temperature fluctuations may affect foraging success even if they do not directly affect prey density.…”

Can Temperature and Water Availability Contribute to the Maintenance of Latitudinal Diversity by Increasing the Rate of Biotic Interactions?

“…Allee et al 1949;Bauwens et al 1995) and, as a consequence, the encounter rate among potentially interacting individuals may also increase (e.g. bees and flowers -Herrera 1995; predator-prey ectothermic interactions - Kruse et al 2008; agonistic interactions in male dragonflies - Baird and May 2003; encounter rate between males and females -Moya- Laraño et al 2007). Also, in animals the probability of entering diapause increases with latitude (e.g.…”