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Prey-predator interactions have been modelled by numerous workers. Ecologists have continuously modified Lotka–Volterra equations in order to provide more realistic descriptions of the complexity of these interactions. The response of predator(s) to increasing prey density can be best described in terms of a functional response, which is an important criterion determining the success or failure of predator(s) to control fluctuating prey populations. The functional response of a predator is further differentiated into Holling’s Type I, II, III, IV and V. We discuss one-prey and one-predator interactions, in which the models are modified by the inclusion of steady-state satiation and growth factors. We review situations where two prey and one predator interact, and vice versa. We also discuss Holling’s Type IV model relevant to competition and food chains. There is a need to examine functional responses as these models were mostly developed by pure mathematicians and their relevance to field conditions remains largely untested. Prey-predator interactions can be affected even by small factors and ecologists should include these models in their experimental design when attempting to predict realistic interactions.

Menochilus sexmaculatus and Propylea dissecta (Coleoptera: Coccinellidae) are predaceous ladybird beetles with immense biological control potential. The morphology of the antennae of the adults along with the diversity and distribution of sensilla were investigated using a scanning electron microscope as they are the main sensory organs involved in chemical communication, thermo-reception, materecognition, gustation, etc. The antennae of males and females in both species were clavate and consisted of three parts: scape, pedicel and a 9-segmented flagellum. The antennae of male and female P. dissecta were significantly longer than those of M. sexmaculatus despite their overall body size being smaller, probably due to the much longer F9 flagellomere in P. dissecta. Antennae of female ladybirds of both species exhibited sexual dimorphism in being longer than those of males. Scape was longer than other antennal parts in both species of ladybirds. There was a great diversity of sensilla with most of them on the ninth-flagellomere. We identified nine types of sensillum: chaetica, trichoidea, basiconica, Bohm bristles, campaniformia, placoidea, coeloconica, sporangia and styloconica. Coeloconica were restricted to flagellomere F8 in male P. dissecta and female M. sexmaculatus, respectively, indicating sexual dimorphism and male-related functions of this sensillum.