Bronswijk, J.E.M.H. van 1991.
The natural history of experimental and applied entomology in The Netherlands (p. 1 )

Velthuis, H.H.W. 1991.
Pollen digestion and its relation to the evolution of sociality in the bees (p. 2-7 )

Schelvis, J. 1991.
Predatory mites (Acari; Gamasida) as specific dung indicators in archaeology (p. 8-13 )

Schelvis, J. 1991.
Lice and nits (Pediculus humanus) from medieval combs excavated in The Netherlands (p. 14-15 )

Booij, C.J.H. & J. Noorlander 1991.
The impact of integrated farming on carabid beetles (p. 16-21 )

Siepel, H. 1991.
Nature restoration and the role of the mesofauna in decomposition of organic matter (p. 22-27 )

Wingerden, W.K.R.E. van, J.C.M. Musters, R.M.J.C. Kleukers, W. Bongers & J.B. van Biezen 1991.
The influence of cattle grazing intensity on grasshopper abundance (Orthoptera: Acrididae) (p. 28-34 )

Hoeven, W.A.D. van der, A. Janssen & R. de Boer 1991.
Is the allergen level of house dust related to age of the house? (p. 35-40 )

Goffau, L.J.W. de 1991.
Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) a new economically imponant leaf miner in the Netherlands (p. 41-45 )

Grijpma, P. & C.P. van de Weerd 1991.
The entomofauna of cones of Larix decidua and L. kaempferi in the The Netherlands (p. 46-51 )

Moraal, L.G. 1991.
Aims of the annual survey of insect infestations on trees and shrubs in forests, roadside plantings and urban plantings in the Netherlands (p. 52-55 )

Loon, J.J.A. van & M.M.M. van Meer 1991.
Chemosensory perception of leaf surface chemicals by ovipositing Pieris brassicae L. butterflies (p. 56-61 )

Piek, T. 1991.
Venoms of the hymenoptera – a lead to new pesticides? (p. 62-67 )

Kroon, A. & A. Veerman 1991.
Quantitative aspects of photoperiodic time measurement in the spider mite Tetranychus urticae (p. 68-73 )

Harrewijn, P., P.G.M. Piron, J. Gut & A.M. van Oosten 1991.
The role of terpenoid end products in development of the aphid Megoura viciae (Buckton) (p. 74-79 )

Ent, L.J. van der & J.H. Visser 1991.
The visual world of the Colorado potato beetle (p. 80-85 )

Schooneveld, H. 1991.
Peptidergic nerve cells deliver multiple messengers for optimiting neuroendocrine coordination in the Colorado potato beetle (p. 86-91 )

Diederen, J.H.B., H.G.B. Vullings & W.F. Jansen 1991.
The functional significance of enhanced endocytosis in flight-stimulated adipokinetic cells in the corpus cardiacum of Locusca migratoria (p. 92-93 )

Oudejans, R.C.H.M., F.P. Kooiman, W. Heerma, C. Versluis, A.J. Slotboom & A.M.Th. Beenakkers 1991.
A new, third, adipokinetic hormone from the migratory locust, Locusta migratoria (p. 94-95 )

Vullings, H.G.B., J.H.B. Diederen & P.N.M. Konings 1991.
The innervation of the adipokinetic cells in the corpus cardiacum of Locusta migratoria (p. 96-97 )

Graaf, D.C. de & F.J. Jacobs 1991.
Humoral response of the honeybee (Apis melifera L.) in relation to Nosema apis Zander (p. 98-102 )

Bruin, J. M.W. Sabelis, J. Takabayashi & M. Dicke 1991.
Uninfested plants profit from their infested neighbours (p. 103-108 )

Elst, I.F.A.M., R. Vernèede & G.A. Pak 1991.
Response of the parasitoid wasp Cotesia glomerata to odour cues from the host-habitat complex (p. 109-114 )

Sütterlin, , G.-J. van der Mey & J.C. van Lenteren 1991.
Distribution in space and time of Trialeurodes vaporariorum (Westwood) on Gerbera: does host plant architecture influence the dispersal and distribution of the whitefly? (p. 115-120 )

Thomas, D.C., P.W.T. Huisman & J.C. van Lenteren 1991.
A study of host plant adaptation in the Glasshouse whitefly Trialeurodes vaporarirorum [sic!] Westwood) (p. 121-122 )

Hogendoorn, K. 1991.
Intraspecific competition in the carpenter bee Xylocopa pubescens and its implications for the evolution of sociality (p. 123-128 )

Eijnde, J. van den & A. de Ruijter 1991.
The use of bumblebee colonies (Bombus terrestris L.) for pollination of glasshouse tomatoes (p. 129-130 )

Kwak, M.M., P. Kremer, E. Boerrichter & C. van den Brand 1991.
Pollination of the rare species Phyteuma nigrum (Campanulaceae): flight distances of bumblebees (p. 131-136 )

Steen, J. van der & A. de Ruijter 1991.
The management of Osmia rufa L. for pollination of seed crops in greenhouses (p. 137-141 )

Blom, J. van der & H. Arce 1991.
Laying workers in africanised honeybees (p. 142-146 )

Koedam, D. 1991.
Rhytmic patterns of stroking behaviour of workers in Tetragonisca angustula (Apidae: Meliponinae) (p. 147-149 )

Strye, M., G. Borremans & F.J. Jacobs 1991.
Monitoring honey-bees: the design of a computer-operated bee counter (p. 150-153 )

Boot, W.J., J.N.M. Calis & J. Beetsma 1991.
Invasion of Varroa mites into honeybee brood cells; When do brood cells attract Varroa mites? (p. 154-156 )

Beerling, E.A.M. & L.P.S. van der Geest 1991.
Microsporidiosis in massrearings of the predatory mites Amblyseius cucumeris and A. barkeri (Acarina: Phytoseiidae) (p. 157-162 )

Heuvel, J.F.J.M. van den, M.A. Goedbloed & D. Peters 1991.
Specific epitopes on the capsid of potato leafroll virus may be involved in aphid transmission (p. 163-168 )

Grijpma, P., J.C. van Lenteren & L.M. van Sonderen 1991.
Host specificity and oviposition behaviour of Telenomus nitidulus, egg parasite of the satin moth, Leucoma salicis (p. 169-170 )

Takken, W. 1991.
A new windtunnel for studies on host-seeking behaviour of mosquitoes (p. 171 )

Menken, S.B.J. 1991.
Does haplodiploidy explain reduced levels of genetic variability in hymenoptera? (p. 172-178 )

Dicke, M., M.W. Sabelis, R.J.F. Bogaers, M.P.T. Alers & I. van Halder 1991.
Kairomone perception by a predatory mite: behavioural analysis of chemoreceptor-carrying extremities (p. 179-184 )

Haccou, P., J.J.M. van Alphen & W. Heitmans 1991.
Optimal clutch size of parasitoids in stochastically fluctuating environments (p. 185-189 )

Wiskerke, J.S.C. & L.E.M. Vet 1991.
Comparison of two Cotesia species foraging for solitarily and gregariously feeding Pieris host species (p. 190-195 )

Drukker, B., J.S . Vaninek, R.N. Coles & H.R. Herren 1991.
Aerial release of Acarine biological control agents on carrier materials (p. 196-201 )

Houten, Y.M. van 1991.
Diapause induction in the thrips predators Amblyseius barkeri and Amblyseius cucumeris (Acari: Phytoseiidae) in Dutch greenhouses (p. 202-207 )

Klerks W. & J.C. van Lenteren 1991.
Natural enemies of Jacobiasca lybica (de Berg): a literature survey (p. 208-213 )