Hemptinne J -L, Dixon A F G, Coffin J
School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich, UK.
Oecologia. 1992 May;90(2):238-245. doi: 10.1007/BF00317181.
Temporal changes in aphid abundance pose a considerable challenge to ovipositing aphidophagous ladybirds, as in order to maximize their fitness they need to synchronize their reproduction with the early development of aphid populations. Field census data and laboratory experiments were used to determine how ovipositing females of the two-spot ladybird, Adalia bipunctata (L.), assess whether an aphid population is suitable for exploitation. In the field, two-spot ladybirds usually laid eggs well before aphid populations peaked in abundance. In the laboratory they showed a marked reduction in their reproductive numerical response in the presence of larvae of their own species but not of other aphidophagous ladybirds. At the highest aphid density this was not a consequence of competition for food between larvae and ovipositing females. In the presence of conspecific larvae gravid females were very active and as a consequence more likely to leave an area, and when confined with other conspecific females or larvae laid fewer eggs and later than females kept on their own. The extent of the inhibition of egg laying is negatively correlated with the rate of encounter with larvae. Thus it is proposed that gravid females appear mainly to use the presence of conspecific larvae to assess the potential of an aphid colony for supporting the development of their offspring.
蚜虫数量的时间变化对正在产卵的食蚜瓢虫构成了相当大的挑战，因为为了使自身适应性最大化，它们需要使其繁殖与蚜虫种群的早期发展同步。利用田间普查数据和实验室实验来确定二斑瓢虫（Adalia bipunctata (L.)）的产卵雌虫如何评估一个蚜虫种群是否适合进行利用。在田间，二斑瓢虫通常在蚜虫种群数量达到峰值之前就大量产卵。在实验室中，在有其自身物种的幼虫存在时，它们的繁殖数量反应显著降低，但在有其他食蚜瓢虫幼虫存在时则不然。在最高蚜虫密度下，这并非幼虫与产卵雌虫之间争夺食物的结果。在有同种幼虫存在时，怀孕雌虫非常活跃，因此更有可能离开一个区域，并且当与其他同种雌虫或幼虫关在一起时，产卵数量比单独饲养的雌虫少且产卵时间更晚。产卵抑制的程度与遇到幼虫的频率呈负相关。因此，有人提出怀孕雌虫似乎主要利用同种幼虫的存在来评估一个蚜虫群体支持其后代发育的潜力。
