Patch exploitation by the parasitoids Cotesia rubecula and Cotesia glomerata in multi‐patch environments with different host distributions

1. We analysed the foraging behaviour of two closely related parasitoid species (Cotesia rubecula and Cotesia glomerata) with respect to leaving tendencies from patches in different environments. We investigated how intrapatch experiences like contact with feeding damage and encounters with hosts influence patch leaving decisions. We also estimated the effect of experiences in previously visited patches on leaving decisions in the present patch. 2. For this analysis we applied the proportional hazards model (Cox 1972) to data collected in three versions of a multiple patch set-up. These set-ups consisted of different host species or combinations of host species: (1) Pieris rapae, (2) Pieris brassicae and (3) both P. rapae and P. brassicae. The larvae of these hosts differ in their spatial distribution on plants: P. brassicae occur in clusters and the distribution of larvae is heterogeneous; P. rapae larvae feed solitarily. 3. The specialist parasitoid C. rubecula used a simple strategy: highest leaving tendency on empty leaves, lower leaving tendency on leaves infested with the non-preferred host P. brassicae, lowest leaving tendency on leaves infested with the preferred host, P. rapae. In the environment with both host species, the leaving tendency only decreased on leaves infested with P. rapae. 4. The generalist C. glomerata used a more complex set of rules. (a) Multiple ovipositions on the present patch decreased the leaving tendency on leaves containing the gregarious host. (b) Once the parasitoid had encountered two or more hosts, it had a lower leaving tendency during subsequent patch visits. (c) The leaving tendency increased with the number of visits on infested leaves. In environments where the less preferred host P. rapae was present, C. glomerata switched to the same simple type of rule as used by C. rubecula. 5. Neither of the two Cotesia species used a count-down rule, in which ovipositions increase the leaving tendency. We discuss how patch exploitation by both Cotesia species compares to the patch exploitation mechanisms as proposed by Waage (1979) and Driessen et al. (1995). 6. We formulate an ‘adjustable termination rate’ model for patch exploitation in both Cotesia species in multi-patch environments.

[1]  J. Waage,et al.  Foraging for patchily-distributed hosts by the parasitoid, Nemeritis canescens , 1979 .

[2]  M. Dicke,et al.  Long-distance assessment of patch profitability through volatile infochemicals by the parasitoids Cotesia glomerata and C. rubecula (Hymenoptera: Braconidae). , 1998 .

[3]  S. Siegel,et al.  Nonparametric Statistics for the Behavioral Sciences , 2022, The SAGE Encyclopedia of Research Design.

[4]  Y. Iwasa,et al.  Prey Distribution as a Factor Determining the Choice of Optimal Foraging Strategy , 1981, The American Naturalist.

[5]  D. Stephens.  Variance and the Value of Information , 1989, The American Naturalist.

[6]  D. Cox.  Regression Models and Life-Tables , 1972 .

[7]  Per Kragh Andersen,et al.  Testing Goodness of Fit of Cox's Regression and Life Model , 1982 .

[8]  M. Dicke,et al.  Volatiles from damaged plants as major cues in long‐range host‐searching by the specialist parasitoid Cotesia rubecula , 1994 .

[9]  M. Strand,et al.  BEHAVIORAL RESPONSE OF THE PARASITOID CARDIOCHILES NIGRICEPS TO A KAIROMONE , 1982 .

[10]  Rhondda Jones,et al.  Seasonal and spatial variation in juvenile survival of the cabbage butterfly Pieris rapae: evidence for patchy density-dependence , 1987 .

[11]  L. Vet,et al.  The role of host species, age and defensive behaviour on ovipositional decisions in a solitary specialist and gregarious generalist parasitoid (Cotesia species) , 1996 .

[12]  P. Haccou,et al.  Effects of intra-patch experiences on patch time, search time and searching efficiency of the parasitoid Leptopilina clavipes (Hartig). , 1993 .

[13]  A. Kacelnik,et al.  A count-down mechanism for host search in the parasitoid Venturia canescens , 1995 .

[14]  M. Dicke,et al.  Response of the braconid parasitoid Cotesia (=Apanteles) glomerata to volatile infochemicals: effects of bioassay set‐up, parasitoid age and experience and barometric flux , 1992 .

[15]  Richard F. Green,et al.  Stopping Rules for Optimal Foragers , 1984, The American Naturalist.

[16]  P. Haccou,et al.  INFORMATION PROCESSING BY FORAGERS: EFFECTS OF INTRA-PATCH EXPERIENCE ON THE LEAVING TENDENCY OF LEPTOPILINA HETEROTOMA , 1991 .

[17]  W. J. Lewis,et al.  Parasitoid foraging and learning. , 1995 .

[18]  J. Kalbfleisch,et al.  The Statistical Analysis of Failure Time Data , 1980 .

[19]  P. Haccou,et al.  The Influence of Larval Dispersal in the Cinnabar Moth (Tyria jacobaeae) on Predation by the Red Wood Ant (Formica polyctena): An Analysis Based on the Proportional Hazards Model , 1985 .

[20]  Louise E. M. Vet,et al.  Learning to discriminate between infochemicals from different plant‐host complexes by the parasitoids Cotesia glomerata and C. rubecula , 1998 .

[21]  E. Charnov.  Optimal foraging, the marginal value theorem. , 1976, Theoretical population biology.

[22]  G. Gort,et al.  Analysing host location in Uscana lariophaga (Hymenoptera: Trichogrammatidae), an egg parasitoid of bruchids (Coleoptera: Bruchidae), using Cox's proportional hazards model , 1995 .

[23]  J. Geervliet.  Infochemical use by insect parasitoids in a tritrophic context:comparison of a generalist and a specialist. , 1997 .

[24]  James N. McNair,et al.  Optimal Giving-Up Times and the Marginal Value Theorem , 1982, The American Naturalist.

[25]  J. Brodeur,et al.  Host species affecting the performance of the larval parasitoids Cotesia glomerata and C. rubecula (Hymenoptera: Braconidae). 2. Comparative suitability of three Pieris species (Lepidoptera: Pieridae). , 1992 .