Observations on the biology of Afrotropical Hesperiidae (Lepidoptera) with particular reference to Kenya. Part 10. Pyrginae, Carcharodini
Author
Cock, Matthew J. W.
text
Zootaxa
2016
4173
4
301
350
journal article
38068
10.11646/zootaxa.4173.4.1
235cd1e5-39f4-43b4-a65a-94daa8e45bec
1175-5326
256597
3E955EB2-79DE-462C-B3EE-E4AF334D1F61
Spialia kituina
Karsch, 1896
De Jong (1978)
placed
S. kituina
in his
asterodia
group, along with
S. asterodia
and
S. agylla
. G.C. Clark (in
Dickson & Kroon 1978
) illustrated a detailed life history of
A
. asterodia
, and
Henning
et al
. (1997)
illustrates a caterpillar and pupa of
S. agylla
.
The
type
locality for
S. kituina
is
Kitui
,
180km
east of
Nairobi
,
Kenya
(
Karsch 1896
,
De Jong
1978
), not Zanzibar as given by
Evans (1937)
.
Pyrgus bettoni
Butler, 1898
described from Maungu, southeast of
Voi
on the
Mombasa
Road
,
Kenya
is a synonym of
S. kituina
. This species is quite widespread in dry forests of
eastern Kenya
extending into the
Rift Valley
(Magadi Road), while
De Jong
(1978)
also gives a record for Logichokio in northwest
Kenya
. It is one of the few entirely endemic Kenyan skippers, although its presence in neighbouring countries is not unlikely.
Normally this is a rare species (
Larsen 1991
), e.g.
Sevastopulo (1974)
records it as uncommon on the outskirts of Makardara and Marere Forests, Shimba Hills. It tends to be found in small groups of two or three, although once I found it common in Kibwezi Forest (
29 Apr 1990
).
Adult behaviour.
Flight is low and rapid interspersed with resting on low vegetation and feeding at low flowers. I have seen a male use a dried grass inflorescence about
50 cm
tall as a perch to defend a territory, returning for short periods to his perch.
Food
plants.
Van Someren
(1974)
gives
Sida
spp. as the food plants in
East
Africa, in which he is followed by
Larsen
(1991)
. I found the caterpillars on a patch of
Hermannia exappendiculata
at the edge of
Jadini Forest
behind
Diani Beach
(
MJWC
90
/109). The following account is based on this material. Similar caterpillars which I was unable to rear were twice found on the same food plant at
Kibwezi Forest
.
Ovum.
The ovum (
Figure 2
) is laid on the abaxial surface of a young leaf, near the margin, or on the terminal, small young leaves. It may be that they are only laid on the youngest leaves, and those I have observed near the margin on the leaf abaxial surface were originally laid there but the leaf has expanded and opened subsequently. Although I believe it correctly identified, the ovum illustrated could be that of
S. zebra
(Butler)
, which also fed upon
H. exappendiculata
in the same area. However, I have associated a slightly different ovum with
S. zebra
(
Figure 27
), which is more globular, with more continuous lateral ridges. The ovum treated as
S. kituina
here (MJWC 90/109) is
0.62mm
in diameter, and has a series of irregular ridge-like protuberances in rows around the circumference, about 20 slightly above the base, a row of 18 above this, then of 14 and finally a circle of six around the micropyle. In some cases the ridges in successive rows run into each other, but often not.
FIGURE 2
. Three views of an ovum of
Spialia kituina
, collected on
Hermannia exappendiculata
, Diana Beach
, 12 Dec 1990; MJWC 90/109.
1
, dorsal view;
2
, dorsolateral view;
3
, lateral view.
Leaf shelters.
The leaf shelters are made by folding a leaf in half upwards and binding the edges together. Usually the whole leaf is used, but one shelter using the distal portion only was found. Older caterpillars seem to move onto younger leaves with successive shelters.
Caterpillar.
There appears to be five instars. In the final instar (
Figure 3
), the caterpillar head measures 2.1 x
1.9mm
wide x high (n=3); dark brown, rugose, shiny; long, erect, pale, simple setae of about
0.35mm
; similar, but dark setae on apices and less densely laterally; face from vertex to base of frons and almost to lateral edge with short, pale, recumbent, aciculate setae, except for a bare patch on each epicranium about one-quarter of the width of the face; these aciculate setae capture and hold white waxy powder at pupation. Pronotum concolorous with body, or paler; a very narrow slightly undulating dark line towards the posterior margin; about 20 long, pale, erect, simple setae. Body yellow-green, dorsal line and two lateral lines darker, scattered yellow-white dots; body covered with short, erect setae, bifurcate just before apex; anal plate with simple setae around margin; legs concolorous; spiracles inconspicuous. The caterpillar is superficially similar to others of the genus, but the uniform concolorous colouring of T1 (brown in the penultimate instar), is distinctive, lacking the contrasting white spots found in other species that I have reared.
FIGURE 3
. Final instar caterpillar of
Spialia kituina
, collected on
Hermannia exappendiculata
, Diana Beach
, 12 Dec 1990; moulted to final instar approximately 16 Dec; pupated 11 Jan 1991; MJWC 90/109A.
1
, dorsolateral view; photographed 20 Dec; 13mm.
2
, lateral view; photographed 27 Dec.
3
, detail of head, anterolateral view; as #2.
In the penultimate instar, the head (
Figure 4
) measures 1.45 x
1.5mm
wide x high (n=2). A
10.5mm
caterpillar in the penultimate instar (MJWC 90/109) had the head brown, with long, pale, erect, simple setae, together with darker ones on apices and laterally; short, pale, recumbent, aciculate setae across face, except for a variable bare patch on each epicranium. Pronotum uniformly brown, except darker on posterior margin. Body dull yellow-green, dorsal line darker, dorsolateral and lateral lines lighter; scattered yellow dots and long, pale, erect setae, bifurcate just before apex.
FIGURE 4
. Penultimate instar caterpillar of
Spialia kituina
, collected on
Hermannia exappendiculata
, Diana Beach
, 12 Dec 1990; photographed 13 Dec; moulted to final instar approximately 16 Dec; 11mm; MJWC 90/109A.
1
, dorsolateral view.
2
, head and thorax, dorsal view.
The preceding two instars are similar. The head of the Ln-2 caterpillar measures 1.1 x
1.1mm
(n=2), while that of the Ln-3 instar measures 0.8 x
0.8mm
(n=1). Given that the ovum is externally only
0.62mm
in diameter (above), there is probably only one earlier instar. The head of the Ln-2 caterpillar is brown rather than dark brown, and there are no dark setae and no area bare of aciculate setae on the face. The head of the Ln-3 caterpillar has rather uniform short, erect, pale setae. The smallest caterpillars feed upon the leaf upper surface and skeletonise it.
Pupa.
Pupa MJWC 90/109
A
(Figure 5.2) was
11mm
long,
3mm
at widest; head, thorax and dorsal abdomen dark; appendages and abdomen ventrally translucent; lightly covered with white waxy powder; spiracle T1
0.76mm
wide (dorso-ventrally),
0.4mm
long (antero-posteriorly), dark and protruding, the posterior margin is a black fluted vertical wall of
0.20mm
, and the anterior portion slopes down to the surface of the pupa; a row of four wax-free patches dorsally on
A
1–3 giving a tessellated appearance; proboscis to end of wing sheaths; cremaster narrow; pupa covered with short, slender, pale, setae except on appendages; no brown plaques discernable. The pupal stage lasts 12–14 days.
FIGURE 5.
Biology of
Spialia kituina
, Kenya.
1
,
Microgasterinae
cocoon reared from caterpillar, collected on
Hermannia exappendiculata
, Kibwezi
, 1 Apr 1989; 5mm; MJWC 89/29B.
2
, pupa, lateral view; collected as caterpillar on
H. exappendiculata
, Diana Beach
, 12 Dec 1990; pupated 11 Jan 1991; photographed 20 Jan; adult 25 Jan; 11mm; MJWC 90/ 109A.
Natural enemies.
Two caterpillars collected at Kibwezi (MJWC 89/29) were parasitized by a solitary larval endoparasitoid
Microgasterinae
, the larvae of which emerged from fifth instar host caterpillars to spin a
5mm
long white cocoon in a very loose flocculence of white silk in the leaf shelter (Figure 5.1). The adult emerged after 11 days.