Skip to main content

Larval morphology of Metaphycus flavus and its role in host attachment and larval cannibalism

  • A. Tena (a1), A. Kapranas (a2), G.P. Walker (a2), F. Garcia-Marí (a3) and R.F. Luck (a2)...

Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50–70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.

Corresponding author
*Author for correspondence Fax: (+34) 96 342 40 01 E-mail:
Hide All
Bartlett, B.R. & Ball, J.C. (1964) The developmental biologies of two encyrtid parasites of Coccus hesperidum and their intrinsic competition. Annals of the Entomological Society of America 57, 496503.
Bernal, J.S., Luck, R.F. & Morse, J.G. (1999a) Host influences on sex ratio, longevity, and egg load of two Metaphycus species parasitic on soft scales: implications for insectary rearing. Entomologia Experimentalis et Applicata 92, 191204.
Bernal, J.S., Luck, R.F. & Morse, J.G. (1999b) Augmentative release trials with Metaphycus spp. (Hymenoptera: Encyrtidae) against citricola scale (Homoptera: Coccidae) in California's San Joaquin Valley. Journal of Economic Entomology 92, 10991107.
Clausen, C.P. (1940) Entomophagous Insects. New York, USA, McGraw-Hill.
Flanders, S.E. (1942) Metaphycus helvolus, an encyrtid parasite of the black scale. Journal of Economic Entomology 35, 690698.
Godfray, H.C.J. (1994) Parasitoids: Behavioral and Evolutionary Ecology. Princeton, NJ, USA, Princeton University Press.
Hagen, K.S. (1964) Developmental stages of parasites. pp. 168246 in DeBach, P. (Ed.) Biological Control of Insect Pests and Weeds. London, UK, Chapman and Hall.
Heraty, J. & Hawks, D. (1998) Hexamethyldisilazane – a chemical alternative for drying insects. Entomological News 109, 369374.
Jervis, M.A., Copland, M.J.W. & Harvey, J.A. (2005) The life-cycle. pp. 73165 in Jervis, M.A. (Ed.) Insects as Natural Enemies: A Practical Perspective. Dordrecht, The Netherlands, Springer.
Kapranas, A., Pacheco, P., Forster, L.D., Morse, J.G. & Luck, R.F. (2008) Precise sex allocation by several encyrtid parasitoids of brown soft scale Coccus hesperidum L. (Hemiptera: Coccidae). Behavioural Ecology and Sociobiology 62, 901912.
Kapranas, A., Wanjberg, E. & Luck, R.F. (2009) Sequences of sex allocation and mortality in clutches of Metaphycus parasitoids of soft scale insects and the prevalence of all-female broods. Ecological Entomology 34, 652662.
Keil, T.A. (1999) Morphology and development of the peripheral olfactory organs. pp. 547 in Hansson, B.S. (Ed.) Insect Olfaction. Berlin, Germany, Springer-Verlag.
Laing, J.E. & Corrigan, J.E. (1987) Intrinsic competition between the gregarious parasite, Cotesia glomeratus and the solitary parasite, Cotesia rubecula (Hymenoptera: Braconidae) for their host, Artogeia rapae (Lepidoptera: Pieridae). Entomophaga 32, 493501.
Maple, J.D. (1954) The eggs and first instar larvae of Encyrtidae and their morphological adaptations for respiration. University of California, Publications in Entomology 8, 25122.
Mayhew, P.J. & van Alphen, J.J.M. (1999) Gregarious development in alysiine parasitoids evolved through a reduction in larval aggression. Animal Behaviour 58, 131141.
Saakyan-Baranova, A.A. (1966) The life cycle of Metaphycus luteolus Timb. (Hymenoptera: Encyrtidae), parasite of Coccus hesperidum L. (Homoptera: Coccidae), and the attempt of its introduction into the USSR. Entomological Review 45, 414423.
Salt, G. (1961) Competition among insect parasitoids. Mechanisms in biological competition. Symposium of the Society for Experimental Biology 15, 96119.
Tena, A., Kapranas, A., Garcia-Marí, F. & Luck, R.F. (2008) Host discrimination, superparasitism, and infanticide by a gregarious endoparasitoid. Animal Behaviour 76, 789799.
Tena, A., Kapranas, A., Garcia-Marí, F. & Luck, R.F. (2009) Larval cannibalism during the late developmental stages of a facultatively gregarious encyrtid endoparasitoid. Ecological Entomology 34, 669676.
van Baaren, J., Boivin, G., Le Lannic, J. & Nénon, J.P. (1997) The male and female first instar larvae of Anaphes victus and A. listronoti (Hymenoptera, Mymaridae). Zoomorphology 117, 189197.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Bulletin of Entomological Research
  • ISSN: 0007-4853
  • EISSN: 1475-2670
  • URL: /core/journals/bulletin-of-entomological-research
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed