I focus on parasites as one of the stressors that can have a strong effect on movement of individuals as well as their population dynamics. Animals living in groups are especially susceptible for parasites due to frequent interactions between individuals. One unresolved question is under what conditions are parasites key regulators of population dynamics?
To address this question, I study at the moment the effect of parasites (i.e. the mite Varroa destructor) on life span, growth and flight performance of individual honeybees [73,94] and colony dynamics and survival during winter . I work together with Coby van Dooremalen and other from the group Bees@wur.
Bees are important pollinators of food crops and wild plants. However current high losses of honeybees seriously threaten crop pollination. The parasitic mite Varroa destructor in combination with one or more stressors, such as diseases, low food availability or pesticides, is considered to be one of the main causes for honeybee colony losses. I studied the effect of different stressors on the performance of individuals and the colony dynamics:
Nkoba, K, S.K. Raina and F. van Langevelde (accepted) Large effect of habitat degradation on species diversity and nest abundance of five Afro stingless bee species in a tropical rainforest, Kenya. International Journal of Tropical Insect Sciences
Nkoba, K., S.K. Raina and F. van Langevelde (2016) A vertical compartmented hive design effective to reduce post-harvest colony loss in Afrotropical stingless bee species (Apidae: Meliponinae). International Journal of Development Research 6: 9026-9034 (PDF)
Blanken, L.J., F. van Langevelde and C. van Dooremalen (2015) Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees. Proceedings of the Royal Society B 282:20151738 (PDF)
Van Dooremalen, C., E. Stam, L. Gerritsen, B. Cornelissen, J.J.M. van der Steen, F. van Langevelde and T. Blacquière (2013) Interactive effect of reduced pollen availability and Varroa destructor infestation limits growth and protein content of young honey bees. Journal of Insect Physiology 59:487–493 (PDF)
Van Dooremalen, C., L. Gerritsen, B. Cornelissen, J.J.M. van der Steen, F. van Langevelde and T. Blacquière (2012) Winter survival of individual honey bees and honey bee colonies depends on level of Varroa destructor infestation. PLoS ONE 7:e36285 (PDF)
Dilution effects and underlying mechanisms
Parasitic infections can reduce fitness of animals, from invertebrates up to large mammals, and infected individuals can transmit the parasite to other organisms, among which wildlife, livestock and people. The disease-diversity relation is one of the central topics in disease ecology, hypothesizing that species diversity reduces pathogen transmission, i.e. the dilution effect. Although mounting evidences have been found, the dilution effect is still highly disputed. Currently I work together with Zheng Huang (a former PhD student) and Fred de Boer on the role of African buffalo and wild suids in wild herbivore communities and livestock that results in either a dilution effect or amplification effect.
Huang, Z.X.Y., F. van Langevelde, K.J. Honer, M. Naguib and W.F. de Boer (2017) Regional level risk factors associated with the occurrence of African swine fever in West and East Africa. Parasites & Vectors 10:16 (PDF)
Huang, Z.Y.X, Y. Yu, F. van Langevelde and W.F. de Boer (accepted) Does the dilution effect generally occur in animal diseases? Parasitology
Huang, Z.Y.X., F. van Langevelde, A. Estrada-Peña, G. Suzán and W.F. de Boer (2016) The diversity-disease relationship: evidence for and criticisms of the dilution effect. Parasitology 143:1075–1086 (PDF)
Huang, Z.Y.X., F. van Langevelde, H.H.T. Prins and W.F. de Boer (2015) Dilution versus facilitation: impact of connectivity on disease risk in metapopulations. Journal of Theoretical Biology 376:66–73 (PDF)
Huang, Z.Y.X., C. Xua, F. van Langevelde, H.H.T. Prins, K. Ben Jebara, W.F. de Boer (2014) Dilution effect and identity effect by wildlife in the persistence and recurrence of bovine tuberculosis. Parasitology 141:981-987 (PDF)
Huang, Z.Y.X., W.F. de Boer, F. van Langevelde, C. Xu, K. Ben Jebara, F. Berlingieri and H.H.T. Prins (2013) Dilution effect in bovine tuberculosis: risk factors for regional disease occurrence in Africa. Proceedings of the Royal Society B 280:20130624 (PDF)
Huang, Z.Y.X., W.F. de Boer, F. van Langevelde, V. Olson, T.M. Blackburn and H.H.T. Prins (2013) Species’ life-history traits explain interspecific variation in reservoir competence: a possible mechanism underlying the dilution effect. PLoS ONE 8:e54341 (PDF)