The consequences of clustering by Aphis fabae foundresses on spring migrant production

Abstract

Aphis fabae (Homoptera: Aphididae) foundresses were shown to have a clustered distribution on leaves of their primary host, Euonymus europaeus. Two field experiments were carried out to determine the costs or benefits of this clustering behaviour to aphid clones. The first experiment, in spring 1996, excluded predators from colonies formed by single fundatrices or clusters of three. No density-dependent effects on colony growth were observed early in the season, but the total production of migrants per foundress was significantly lower for clustered foundresses. This demonstrated that there was no synergistic effect of group feeding on clonal performance. All colonies were initiated on randomly selected leaves and all grew successfully, therefore clustering was not due to a shortage of feeding sites. The second experiment, in spring 1997, tested whether natural enemies cause selection for selfish herding by the foundress generation. Colonies were initiated by one or three foundresses, but half were left unbagged. If natural enemy attack is a selective force inducing clustering behaviour in foundresses, the costs of clustering should have been reduced or negated in unbagged colonies. Colonies grown from clusters produced significantly fewer migrants per foundress, irrespective of bagging treatment. Other potential factors causing clustering behaviour are discussed.

Model complexity affects transient population dynamics following a dispersal event: a case study with pea aphids

“…This effect may not be ubiquitous, as other work found no effect of group size on aphid performance (Messina 1993, Hodgson andGodfray 1999). A higher fecundity would produce higher transient peaks (Fig.…”

Divergent responses of two cereal aphids to previous infestation of their host plant

“…In the preference test, D. noxia adults avoided leaves from R. padi-infested plants (Table 2), and some of these leaves sustained direct feeding damage. Aphid feeding can alter source-sink relationships of leaves and boost concentrations of limiting nutrients (references in Hodgson & Godfray, 1999;Burd, 2002). A similar contrast between local and systemic effects could explain why D. noxia adults avoided leaves from D. noxia-infested plants even though population growth was not slowed on whole plants that had been infested by D. noxia.…”

“…In the field, colonies of D. noxia are unlikely to encounter local feeding damage by R. padi because the two species occur in different locations on shared host plants (Bergeson & Messina, 1998). Aphid feeding can alter source-sink relationships of leaves and boost concentrations of limiting nutrients (references in Hodgson & Godfray, 1999;Burd, 2002). Feeding damage by D. noxia causes significant increases in the concentrations of essential amino acids, as measured in exudates from aphid stylets as well as in exudates from infested vs. uninfested leaves (Telang et al, 1999;Sandström et al, 2000).…”

Consequences of foundress aggregation in the brown citrus aphid Toxoptera citricida

“…Although individual adults suffer reduced longevity and fecundity at 27°C relative to lower temperatures, nymphal developmental time is minimised and a large proportion survives to adulthood. Hodgson and Godfray (1999) measured a ®tness cost of clustering by foundresses of A. fabae without detectable bene®ts, although the level of predation in the study appeared to be low. Bene®ts of aggregation under the in¯uence of predation have been demonstrated tentatively for Schizolachnus pineti (F.) (Kidd, 1982), Aphis varians Patch (Turchin & Kareiva, 1989), and Uroleucon nigrotuberculatum (Olive) (Cappuccino, 1988).…”