Exploring insect biodiversity: the parasitic Hymenoptera, chiefly Chalcidoidea, associated with seeds of asphodels (Xanthorrhoeaceae), with the description of nine new species belonging to Eurytomidae and Torymidae
Author
Delvare, G.
Author
Escolà, A. Ribes
Author
Stojanova, A. M.
Author
Benoit, L.
Author
Lecomte, J.
Author
Askew, R. R.
text
Zootaxa
2019
2019-05-06
4597
1
1
90
journal article
26921
10.11646/zootaxa.4597.1.1
0bffa033-64f0-4e6f-ba44-287e52d7c2f9
1175-5326
2667950
F8FD30CA-1B84-4134-91BC-B69736DB0EA8
Eurytomidae
Eurytomidae
is by far the best represented chalcidoid family in asphodel seeds, with the seed-eating
Bruchophagus
species supporting a parasitoid fauna that includes the eurytomid genera
Eurytoma
Illiger
and
Aximopsis
Ashmead.
Species of
Eurytoma
were reared from samples of asphodel fruits that always also produced
Bruchophagus
, and we believe that
Eurytoma
behave as parasitoids of
Bruchophagus
in the seeds, although the possibility that larvae of
E. asphodeli
are partly phytophagous is discussed below.
Segmentation of the antenna.
The antenna of
Eurytomidae
is composed of a basal scape followed by a pedicel and a multisegmented flagellum. The flagellum is composed of a single anellus which lacks MPS, a funicle of four to six segments and an apical clava of up to three segments (
Figs 10D, 10E
,
16C, 16D
,
25C
). The anellus is designated the first flagellomere, the first funicle segment (F1) is the second flagellomere, F2 is the third flagellomere and so on. Variation in segmentation between the studied species occurs in two regions of the antenna.
Firstly, flagellomere 7 is incorporated in the clava in females of most species so that the clava is preceded by a 5-segmented funicle (
Figs 16C
,
25C
), but in the first of the newly described
Bruchophagus
species flagellomere 7 is the last segment in a 6-segmented funicle, being separated from flagellomere 8 by a short petiole (
Fig. 10E
).
FIGURE 8
. ML tree figuring the relationships of the
Eurytomidae
based on the barcoding fragment of the mitochondrial gene
CytB.
Annotations identical to those of the Fig. 7.
FIGURE 9
. ML tree figuring the relationships of the
Eurytomidae
based on the barcoding fragment of the nuclear gene
EF1-α.
Annotations identical to those of the Fig. 7.
The second region of segmental variation is the clava, and this may often be appreciated with certainty only after microscopic examination. Three transverse rows of linear sensilla on the clava of most species indicate a trimerous condition but microscopic examination shows that in some species the two last flagellomeres are actually fused and that there is no suture between them, the clava then being effectively 2-segmented (
Figs 12E
,
16D
,
20B
,
21D
). This is the condition in apparently all
Eurytoma
species and in many species of
Bruchophagus
. It is seen in the species illustrated by
Lotfalizadeh
et al
. (2007)
and referred to as ‘
Bruchophagus
Alicante’, here described as
Bruchophagus lecomtei
Delvare
sp. nov.
.
Eurytomidae
associated with asphodels.
A key to the eleven species of
Eurytomidae
found associated with asphodels in Europe follows. In using the key it is essential to ensure that the true condition of the clava is recognised, requiring a carefully check of the segmentation of the flagellum as there is often a false suture, situated at the apex of the second sensilla row of the clava, between the supposedly penultimate segment and the terminal one.
Eight new species are described with observations on all species, and
E
.
asphodeli
is redescribed with an account of its considerable variation.