Energy balance in Speliphron violaceum (Hymenoptera) and use of meconium weight as an index of bioenergetics components.

Speliphron violaceum deposits its larva and a few paralysed spiders inside the holes of electrical sockets. The larva feeds on the spiders, completes development in 6 days and emerges after 18 days of pupation. When provided with spiders to the maximum capacity of the hole, a larva consumed 1.746 KJ and converted 1.360 KJ. Restriction of the quantity of spiders provided, resulted in decreased consumption and extension of larval duration to 7 or 8 days. Consumption of 0.710·718 KJ was the minimum requirement for the completion of larval development. Despite variations in food consumption, assimilation efficiency of the larva remained constant around 97%. Gross production efficiency of the larvae averaged 77%. Larvae ingesting different amounts of host energy emerged with a wide range of body weight (16-62 mg). The efficiency with which pupal energy is transferred to adult was around 30%. Dry weight of meconium egested by the test individuals varied from 1.3 to 4.6 mg. Using simple regression equations, it is possible to predict the bioenergetics components of S. violaceum from the dry weight of meconium.