Antipredator Defense as a Limited Resource : Unequal Predation Risk and

INSECTS WITH PARENTAL INSTINCTS More than two centuries ago, a Swedish scientist named Modeer described what appeared to be maternal behavior in the acanthosomatid shield bug Elasmucha grisea. He noted that the female did not fly away when an intruding object threatened her compact egg mass; instead, she remained steadfast and tilted her body towards the object (Tallamy). Unfortunately, this evidence, no matter how well documented, was not enough to convince countless people of the possibility of insects having parental instincts. The acknowledgement of parental behavior in insects was not a widely accepted idea for a number of years. Many people believed insects were too primitive to care for their young and that only when physical conditions became extremely severe were insects capable of expressing paternal abilities. The traditional view of maternal care is that it is an exceptional and relatively recent evolutionary leap forward (Tallamy). Fortunately, the assumptions made about maternal care in insects do not have to be accepted or rejected based only on faith or an educated guess; today it is possible for these predictions to be empirically tested so that the data may be recorded and analyzed. The following experiment is just one example of the various ways in which ideas regarding insects and maternal care may be effectively evaluated. Reginald B. Cocroft, of the Neurobiology and Behavior Department at Cornell University in Ithaca, New York, researched insects known as Umbonia crassicornis, or the thornbug treehopper. U. crassicornis offspring thrive in large aggregations on the often exposed stems of host-plants. These offspring are incredibly vulnerable, making them easy targets and subject to intense predatio... ...ymphs unequally. The mother distributed her protection equally throughout the entire aggregation along the length of the branch. Main Points: Location in relation to the mother is possibly competitive Location independent of the mother is possibly competitive, but only exploitation competition Signaling is not competitive for maternal care, it is cooperative and the mother distributes protection along the aggregation equally. WORKS CITED Cocroft, Reginald B. 2002. Antipredator Defense as a Limited Resourse: Unequal Predation Risk and Broods of an Insect With Maternal Care. Behavioral Ecology, 13, 1, 125-133. Tallamy, D. W. and C. Schaefer. 1997. Maternal behavior in the Hemiptera: Ancestry, Alternatives, and Current Adaptive Value. pp. 94-115, In B. Crespi and J. Choe (eds.). Social Behavior in Insects and Arachnids. Cambridge University Press, Cambridge.