Seventh International Congress of Hymenopterists

7 th International Congress of Hymenopterists
20-26 June 2010, Kszeg Hungary
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a relatively high chromosome number, n = 9. In other groups of the superfamily Chalcidoidea
that were supposed to be entirely high-numbered, i.e. Encyrtidae (n = 8-12) and Eurytomidae
(n = 9-10), species with lower chromosome numbers have been recently detected. For
example, n = 5, 6, and 7 were found in Eurytoma compressa (Fabricius), Eu. serratulae
(Fabricius), and Eu. robusta Mayr respectively. These species are likely to form a wellsupported
clade within their genus. Another originally high-numbered chalcid family,
Aphelinidae, also harbours groups with lower chromosome numbers, i.e. all Aphelininae and
a few species of Encarsia. Species with higher n values (7 to 10) are now detected in the
family Eupelmidae that generally has lower chromosome numbers (n = 5-6). In addition, n =
10 has been recently found in two species of the genus Podagrion, whereas n = 4-6 were
detected in other Torymidae. Among the "low-numbered" families, n = 6 has been found in
the first studied species of the family Agaonidae, Blastophaga psenes (Linnaeus). The
karyotype containing five large metacentrics and a small subtelocentric or acrocentric is
considered the ground plan feature of the common lineage that includes Torymidae,
Ormyridae, and Agaonidae. The same karyotype structure is also found in Euderomphale
chelidonii Erdös that belongs to Euderomphalini, the most basal tribe of the subfamily
Entedoninae (Eulophidae). In the superfamily Cynipoidea that generally contains highnumbered
species (n = 9-11), low chromosome numbers were detected in the genera Andricus
(Cynipidae, n = 5-6) and Leptopilina (Figitidae, n = 5). Chromosomal characters can be used
in species-level taxonomy of certain genera of parasitic wasps that belong to the Chalcidoidea
and Cynipoidea. For example, Metaphycus flavus (Howard) and M. luteolus (Timberlake)
(Encyrtidae) both have n = 10, whereas M. angustifrons Compere has n = 9, and M. stanleyi
Compere has n = 5. Analogously, n = 10, 9, and 5 were found in Leptopilina heterotoma
(Thomson), L. boulardi Barbotin, Carton et Keiner-Pillault, and L. clavipes (Hartig)
respectively.
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Evolution of solitary and gregarious development in parasitoids: what we can learn
from Entedon wasps (Chalcidoidea: Eulophidae)
Alex Gumovsky
Schmalhausen Institute of Zoology, 15 Bogdan Khmelnitsky St., 01601 Kiev-30, Ukraine;
gumovsky@izan.kiev.ua, entedon@gmail.com
Nominal difference between solitary and gregarious parasitoids concerns number of siblings
developing in the same host. However, the ability to be gregarious may concern degree of
tolerance between sibling larvae, rather than simply number of the eggs laid. Wasps of the
genus Entedon are larval or egg-larval, gregarious or solitary endoparasitoids of Coleoptera
(mostly weevils and bean beetles). Evolution of life history traits in this genus was
reconstructed by phylogenetic analysis of nuclear ribosomal (D2 of 28S) and mitochondrial
(COI and Cyt B) gene regions. The analysis suggests that gregarious parasitism originated
more than once in larval and egg-larval parasitoids. Also, the egg-larval parasitism is rather
common (or even predominant) parasitism in the genus. The preimaginal development also
differs in solitary and gregarious parasitoids. The solitary parasitoids physically eliminate
other rival larvae during their first instar, which is armed with sharp mandibles. In egg-larval
gregarious parasitoids the active “fighting” first instar is ommited: it is embryonized and the
early development of the larva takes place within an extraembryonic cellular membrane. The
larva, which corresponds to the second instar of solitary Entedon species, is formed directly
from the proliferating cells inside this extraembryonic membrane. This embryonization of
“fighters“ may be an approach to avoid killing of siblings by aggressive first instars.
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