THE FUNCTIONAL RESPONSE, WHIT DIFFERENT FLOWERS FOODS SUPPLY, OF HIPPODAMIA VARIEGATA (Goeze) ADULTS (COLEOPTERA: COCCINELLIDAE) IN LABORATORY

Abstract

Functional response (FR) of the ladybeetle adults, Hippodamia variegata (Goeze) (Coleoptera, Coccinellidae) to varying densities (5, 10, 20, 40, 60 and 80) of third instar nymphs of Acyrthosiphon pisum (Harris) in the aphid range 1-40 was assessed in a growth chamber (23±2 ºC, 41±10% relative humidity, and photoperiod 16L:8D), reared on Phaseolus vulgaris (L.). The effect on the FR of the following factors was studied: (i) different sexes (male and female), (ii) different levels of aphids satiety (24 and 48 hours), (iii) different flowers foods supply (Brassicaceae, Apiaceae and Asteraceae) and (iv) different experimental arenas (petri dishes and alfalfa plants). The logistic approach showed a type II functional response. The males consume less aphids than females (a mean reduction of 53.2% in petri dish, and 71.1% in alfalfa plant). The attack coefficients (a) and the handing times (Th) were, generally, majors in the count realized to 24 hrs., than to 48 hrs. and in petri dishes, compared with the values realized on alfalfa plants and, in both cases, when the flowers supplied was Brassica nigra. The presence of floral resource plants from B. nigra and, with less impact, Daucus carota enhances the consumption of H. variegata and, females are most effective as predators than males.