INTERSPECIFIC HOST DISCRIMINATION AND COMPETITION IN APOANAGYRUS (EPIDINOCARSIS) LOPEZI AND A(E)DIVERSICORNIS, PARASITOIDS OF THE CASSAVA MEALYBUG PHENACOCCUS-MANIHOTI
Jwam. Pijls et al., INTERSPECIFIC HOST DISCRIMINATION AND COMPETITION IN APOANAGYRUS (EPIDINOCARSIS) LOPEZI AND A(E)DIVERSICORNIS, PARASITOIDS OF THE CASSAVA MEALYBUG PHENACOCCUS-MANIHOTI, Ecological entomology, 20(4), 1995, pp. 326-332
1. Choice experiments on interspecific host discrimination in A. lopez
i and A. diversicornis were carried out on discs of cassava leaf conta
ining four hosts (P. manihoti) that had been parasitized by the other
species and four unparasitized hosts. 2. A. lopezi accepted both host
types equally for oviposition, whereas A. diversicornis accepted fewer
hosts that had been parasitized by A. lopezi than unparasitized ones.
A. diversicornis is therefore capable of interspecific host discrimin
ation, but such a capability was not demonstrated for A. lopezi. 3. Su
rvival probability in singly pardsitized hosts was 0.85 for both paras
itoid species. When the time interval between ovipositions was 2 h or
less, survival in multiparasitized hosts was 0.68 for A. lopezi and 0.
17 for A. diversicornis, irrespective of priority. Increasing A. lopez
i priority to 24 +/- 2 h did not increase A. lopezi survival. A. diver
sicornis survival, however, increased to 0.43 when A. diversicornis wa
s given 24 +/- 2 h priority. A. diversicornis eggs took 19 h longer th
an A. lopezi eggs to hatch. This could explain the difference in compe
titive abilities in multiparasitized hosts. 4. The observed difference
in host selection behaviour between A. lopezi and A. diversicornis is
in accordance with the different benefits of multiparasitism: A. lope
zi gains more than A. diversicornis because of its superior within-hos
t competitive abilities. 5. Neither species avoided multiparasitism co
mpletely. The low survival probability of A. diversicornis in multipar
asitized hosts may partly explain its failure to establish when introd
uced into Africa as part of a biological control programme of P. manih
oti.