Oviposition site choice by female mosquitoes, Aedes aegypti (L) (Diptera: Culicidae), was affected by rearing them in water treated with 0.016% of the repellent Mozaway trade mark containing citronella and neem. Given a choice between a bowl of repellent-treated and a bowl of untreated water, Ae. aegypti reared in untreated water strongly preferred to oviposit on the clean water (93-98%) instead of repellent-treated water. This demonstrates effective deterrence of oviposition by dilute Mozaway trade mark. Those reared in repellent-treated water were less deterred: 38-46% of their eggs were laid on the repellent-treated water and 54-62% on the clean water. Evidently the female mosquitoes reared in repellent-treated water were conditioned against oviposition site deterrence, as shown when choice tests were conducted 6 days post-emergence from the treated water. This demonstrates learning and memory in the mosquito Ae. aegypti, with implications for dengue vector surveillance and control.

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The roles of eidetic imagery and orientational cues, respectively, in the discrimination of visual patterns by honeybees (Apis mellifera) were evaluated by training the bees to discriminate between patterns consisting of periodic, black and white square wave gratings. Training and tests with a number of different pairs of patterns revealed that bees use orientational cues almost exclusively, if such are present, and make use of eidetic images only when orientational cues are not available. On the other hand, if a pattern carries strong orientational cues, bees learn the orientation even if it is irrelevant to the discrimination task on which they are trained.

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The ability of honeybees (Apis mellifera) to learn and recognise peripherally presented patterns was investigated by training bees in a Y-maze which presented patterns on the side walls, the ceiling or the floor. We found that pattern orientation is learnt and recognised in the lateral and frontal visual field, but not in the dorsal or ventral fields. Colour information, in contrast, is used in the lateral and frontal as well as the ventral visual field, but not in the dorsal field. If pattern orientation is different on opposite sides of the visual field during training, both patterns are learned, but each on its own is sufficient for the bees to recognise the learnt stimulus. However, unilaterally learnt pattern information, be it orientation or colour, cannot be accessed when the test pattern is viewed on the other side. That is, interocular transfer of such information does not occur.