METABOLIC RATES OF PITBUILDING AND NON-PITBUILDING ANTLION LARVAE (NEUROPTERA, MYRMELEONTIDAE) FROM SOUTHERN AFRICA

Hourly metabolic rates, measured as oxygen consumption, were relativel y high from 1000 to 2100h compared with 2200 to 0500h for Cueta sp., w hereas Furgella intermedia exhibited a peak in the afternoon, from 130 0 to 1700h. The resting metabolic rates of Cueta sp., F. intermedia an d Palpares annulatus were between 5.4-8.9% of the expected values for similar-sized poikilothermic invertebrates. These values indicate low energy demands, which is crucial to survive prolonged periods of starv ation. The non-pitbuilding antlion larva, F. intermedia, was generally more active than Cueta sp., with an unexpectedly high specific metabo lic rate fbr its body size. Furgella intermedia had lower Q(10) values between 10-30 degrees C than the pitbuilder Cueta sp., implying a lar ger metabolic tolerance to these temperatures. The increase in metabol ism after feeding (ranging between 2.8-3.7 times pre-feeding metabolis m) was lowest for the larger P. annulatus, indicating low feeding cost s for this species. (C) 1997 Academic Press Limited.