Behavioural energetics of some insects

Abstract

Foraging behaviour of insects includes the following energy-requiring processes: (i) location and (ii) gathering. Some insects do incur additional energy cost on transporting and storing food. Energy cost of foraging ranges from 2 to 5 % of the energy gained in bees and wasps. Initiation of flight, in large and insulated insects obligatorily requires 'warming-up' of muscle temperature and maintenance of endothermy by over 20°C above the ambient. Over-heating is avoided by pumping the cooler abdominal blood into the hot thorax. Pollinating insects include (i) hovering high-energy foragers, which expend more energy and visit more flowers per unit time and (ii) walking low-energy foragers, which expend less energy and visit few flowers per unit time. Decreasing of "wing loading" is another strategy adopted by saturniids, which do not feed as adults. Most bees forage, when flowers are just blooming, and when they have maximum nectar reward to offer. From the model study on energy cost of oviposition, it has been shown that Sceliphron violaceum makes greater and greater effort to complete the process of food provisioning and sealing the larval nest, when it has invested more and more energy on foraging and provisioning spiders to the larviposited young ones.