Vespula germanica

In southern Australia, the native Polistes humilis was the predominant social wasp prior to the arrival of the exotic Vespula germanica (Hymenoptera: Vespidae). Both species forage for similar resources (water, pulp, carbohydrate and protein prey), ... prey morphological identification was complemented by sequencing fragments of the mitochondrial 16S rRNA gene. ...Extent of overlap between V. germanica and P. humilis The low value of Schoener’s index of food overlap between V. germanica and P. humilis suggests that competition for food may not exist between the two wasps. However, closer examination of the composition of prey implies that a single overlap value may not be suitable to use in this situation, and Levin’s asymmetric index, showing a strongerimpact of V. germanica on P. humilis, but not of P. humilis on V. germanica, may be more appropriate. ...Also, almost 14% of all V. germanica foragers return with prey compared to only 8% of P. humilis. This suggests that P. humilis may not be a superior competitor over V. germanica. It is therefore possible that even if Lepidoptera is not a limiting resource, V. germanica might still have a detrimental effect on the lepidopteran population and thus on P. humilis, especially if the exotic wasps reach high densities.(Kasper et al., 2004);

In summer, kaka Nestor meridionalis obtained most of their daily energy requirements from honeydew excreted by the scale insect Ultracoelostoma assimile, The availability of the major remaining source of energy, honeydew, is greatly reduced by introduced wasps (Vespula germanica and V. vulgaris) at certain times of the year (Moller& Tilley, 1989; personal observations). Honeydew is a sugary exudate produced by the scale insect Ultracoelostoma assirnile (Homoptera: Margarodidae) (Crozier, 1981; Grant & Beggs, 1989) and is found on all beech species except silver beech N. menziesii (Wardle, 1984). (Beggs, & Wilson, (1991)

V. germanica requires large quantities of protein to rear its brood. Sources of protein are typically insects and carrion but they are also predatory on nestling birds (Moller, 1990). The quantity of arthropods collected by foraging wasps is remarkable, with a recorded maximum annual collection of 99kg of prey by a single, overwintered nest in New Zealand (Harris, 1996). Prey was mainly flies together with honey bees, moths and spiders and bird remains. This weight of prey is approximately equivalent to 3.5 million blowflies. Where the density of nests is high, wasps can destroy virtually all insect life in a local area with the subsequent disappearance of insectivorous birds (Barr et al., 1996). In parts of Tasmania where the wasps had collected all other insect life, they were observed preying cannibalistically on each other (Spradbery, 1988). (CABI, acesso em 20/06/2021)