Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire ST5 5BG, Newcastle, UK.
Malar J. 2012 Jan 27;11:27. doi: 10.1186/1475-2875-11-27.
Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes.
A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding.
Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns) and olfactory cues (presence and absence of cheese or Citronella smell) with the reinforcing stimuli (bloodmeal quality) and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood) was associated with an innately preferred cue (such as a darker visual pattern). However, the use of too attractive a cue (e.g. Shropshire cheese smell) was counter-productive and decreased learning success.
The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control.
记忆和学习是人类病原体昆虫媒介生态学的关键方面，因为它们可能影响媒介与宿主之间的接触。尽管具有这种流行病学重要性，但仅有少数研究调查了昆虫媒介物种的联想学习，也没有研究过疟蚊。
开发了一种简单的行为测定法，用于研究非洲主要疟蚊种冈比亚按蚊的视觉和嗅觉联想学习。两种对比的膜质量或血液适口性水平被用作在吸血期间进行双向调节的强化刺激。
在这种实验条件下，冈比亚按蚊雌性很快学会将视觉（棋盘和白色图案）和嗅觉线索（奶酪或香茅气味的存在与否）与强化刺激（血餐质量）联系起来，并在长达三天的时间内记住这种联系。联想学习随着使用的调节刺激的强度而显著增加。重要的是，当将积极的强化刺激（可口的血液）与先天偏好的线索（如较暗的视觉图案）相关联时，学习有时会更快。然而，使用过于吸引人的线索（例如什罗普郡奶酪气味）会适得其反并降低学习成功率。
这些结果解决了蚊子生态学中的一个重要知识空白，并强调了联想记忆在冈比亚按蚊寻找宿主和吸血行为中的作用，这对媒介控制具有重要的潜在意义。
