Observations on the Biology of Afrotropical Hesperiidae (Lepidoptera). Part 5. Hesperiinae incertae sedis: Dicotyledon Feeders
Author
Cock, Matthew J. W.
C / o CABI Europe - UK, Bakeham Lane, Egham, TW 20 9 TY, UK (e-mail: m. cock @ cabi. org; mjwcock @ btinternet. com)
m.cock@cabi.org
Author
Congdon, Colin E.
African Butterfly Research Institute (ABRI), P. O. Box 14308, Nairobi, Kenya (e-mail: colin. congdon @ gmail. com)
colin.congdon@gmail.com
text
Zootaxa
2013
2013-10-25
3724
1
1
85
http://dx.doi.org/10.11646/zootaxa.3724.1.1
journal article
134452
10.11646/zootaxa.3724.1.1
3fe084ed-d367-4d5a-9ed0-48882760ba96
1175-5326
5267833
7D05BB2E-4373-4AFB-8DD3-ABE203D3BEC1
Gorgyra bibulus
Riley, 1929
(in
Eltringham
et al
. 1929
)
This localised species was described from the slopes of Mt
Kenya
(
Eltringham
et al
. 1929
) and is also found in
Tanzania
(
Kielland 1990
) and
Uganda
(
Evans 1937
). However, the specimens reported from
Nigeria
by
Evans (1937)
are from
Cameroon
(
Larsen 2005
). It is found in forests, highland forests and forest margins and adults settle on low vegetation and flowers according to
Kielland (1990)
.
Food plants
Van Someren (1974)
recorded the food plant as
Drypetes gerrardii
in East Africa; at that time
Drypetes
was placed in
Euphorbiaceae
, but it is now placed in
Putranjivaceae
. This record is repeated by subsequent authors (
Heath
et al
. 2002
), or simplified to
Drypetes
(
Sevastopulo 1975
,
Larsen 1991
,
Ackery
et al
. 1995
). In the 1990s, ABRI collectors discovered that
Rourea thomsonii
(Connaraceae)
is a food plant in Gatamayu Forest,
Kenya
(
Figure 5
), and the early stages that MJWC collected there with an ABRI collector on
4 Jul 1998
(98/201) are described and illustrated below. Probably, this ABRI food plant record is the origin of the record of
R. thomsonii
in
Heath
et al
. (2002)
. The record from
Drypetes gerrardii
has not been repeated since
Van Someren (1974)
, and the possibility of a misidentification or error cannot be discounted.
Leaf shelters
The stage 1 and stage 2 shelters (
Figures 5
and
6.1
) are two-cut shelters from edge of the leaf; the shelter lids are broad, the two cuts being at right angles to the leaf edge, so that the bridge is as wide as the shelter, and the resultant flap is folded under.
FIGURE 4.
Adult male
Gorgyra bibulus
, collected as final instar caterpillar 4 Jul 1998 on
Rourea thomsonii
, Gatamayu Forest
, Kenya; adult 28 Jul, 98/201B.
One stage 2 shelter measured 20 x
7mm
with a
13mm
penultimate instar (98/201D); the shelter lid was raised from the leaf by pulling the two narrow ends together with silk. Another stage 2 shelter contained a
14mm
penultimate instar caterpillar ready to moult (98/201E;
Figure 6.1
); one end of the shelter was closed but not sealed.
Two final instar caterpillars were field collected. The smaller
19mm
caterpillar (97/201C) was in a shelter made on a
100mm
leaf using the distal half, a large flap having been folded under; most of the feeding was basal to the shelter and the midrib was completely bare for
15mm
immediately basal to the shelter (
Figure 6.2
). The shelter of the larger,
20mm
caterpillar (98/201B) was clearly an earlier version of the pupal shelter described below. On a leaf of
65mm
, the basal
27mm
had been folded over upwards, and most of the leaf distal to this had been eaten (or cut off). The caterpillar pupated on 12 July, eight days after collection, so this shelter seems to have been constructed during the final instar for pupation.
A pupal shelter found in the field (
Figure 6.3
, 98/201A) was formed in a leaf originally
45mm
long, which had become dead and brown because of the caterpillar’s feeding. The distal half of the leaf was eaten (or cut off) except for the midrib and a few scraps; the basal half was folded over upwards along one side of the midrib until flat, forming a shelter
22mm
long; the portion along the midrib formed a tube; strands of tough brown silk along the edge of this tube held the shelter together; the basal end of the tube was sealed shut, and the distal end had a round exit hole lined with silk; the inside of the tube was lined with silk and covered with white waxy powder which was also on the pupa; an adjacent leaf was also heavily eaten or cut back, dead and brown, and the remaining 25 x
15mm
portion dangled alongside the pupal shelter, but this may have been fortuitous rather than normal.
Ovum
Oviposition is concentrated on the youngest red-green flush leaves. At this stage the leaves are still folded in half along the midrib, and the ova are inserted between the two halves of the leaf, some at the margin, but others well inside. The ovum is stuck to one half of the leaf by its base, and to the other at the micropyle. Several ova can be found close together. Hence, for example, one clump of about ten flush leaves on a regenerating cut branch had nine caterpillars in stage 1 shelters (
Figure 5
). The ovum (
Figure 7
) is white, about
0.77mm
(n=4) in diameter,
0.41mm
high (n=2), it is flattened dorsally and widest a little above the base. It is finely sculptured with horizontal rows of adjacent polygonal pits extending almost to the micropyle, about
50 in
total around the circumference where the ovum is widest. About half the shell of the ovum is eaten by the newly hatched caterpillar.
FIGURE 5.
Rourea thomsonii
, a food plant of
Gorgyra bibulus
with feeding and leaf shelters (arrows), Gatamayu Forest, Kenya, 4 Jul 1998; 98/201M.
Caterpillar
The first instars are green with a black head, 1.04 x
0.96mm
wide x high (n=6) in instar n-2. In the penultimate instar (98/201D,
Figure 8
) the head is blackish, rugose, oval, slightly wider basally, slightly indented at vertex, 1.63 x
1.46mm
wide x high (n=3); T1 concolorous; body green with diffuse pale subdorsal lines; faint brown semicircular mark on anal plate; spiracles pale, inconspicuous; legs concolorous. The newly moulted penultimate instar measured
8mm
(98/201J), and a premoult caterpillar (98/201E) measured
14mm
.
The final instar caterpillar is similar to earlier instars. Based on individual 98/201B (
Figure 9
):
20mm
; head oval with slight indentation at vertex, 2.2 x
2.71mm
wide x high (n=1), brown, posterior margin black, rugose; T1 concolorous; body yellow-green, more yellow in transverse folds at posterior of each segment, darker green dorsal line; T1–T2 more slender than following segments; anal plate with weak quadrate reddish mark; spiracles pale, inconspicuous; legs concolorous.
FIGURE 6.
Leaf shelters of
Gorgyra bibulus
on
Rourea thomsonii
, collected 4 Jul 1998, Gatamayu Forest, Kenya; the lines in the background are 8mm apart.
1
, stage 1 shelter on left, 98/201E; stage 2 shelter on right, 98/201F;
2
, stage 3 shelter, 98/201C;
3
, pupal shelter, 98/201A.
FIGURE 7.
Ovum of
Gorgyra bibulus
, on leaf of
Rourea thomsonii
, Gatamayu Forest
, Kenya, 4 Jul 1998, 98/201K.
1
, as laid in a folded very young leaf; 2, dorsal view with part of the facing leaf surface adhering on top.
Pupa
The pupa (
Figure 10
) is supported by the cremaster and a weak, vestigial silk girdle;
18mm
long; matt, dark brownblack; wing cases brown; a bifurcate frontal projection; proboscis extends
1.4mm
beyond wing cases (98/201D); pupa covered with very short, pale setae, which are longer on the anterior and posterior parts of the eye. A male (
Figure 4
, 98/201B) completed pupation in 16 days.
Natural enemies
A
7mm
n-2 instar caterpillar in a stage 2 shelter (98/201H) was dead, together with four euplectine larvae, which had become black naked pupae by 11 July and adults emerged 16 July. The field collected pupa (98/201A) was parasitized by a large (
8.6mm
) ichneumonid (predominantly yellow, abdomen brown; head, forecoxa, and central dorsal part of thorax black; hind tarsi dark) which emerged on 22 Jul, 18 days after collection.