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Volume 24, Number 1
19
STUDIES ON THE BIOLOGY AND SEASONAL HISTORY OF POLYDORUS ARISTOLOCHIAE (PAPILIONIDAE)
G. H. Munshi and S. A. Moiz
Agric. College & Agric. Research Institute, Tandojam, West Pakistan
Polydorus aristolochiae (Fabricius) is the commonest large tailed, black butterfly of Indo-Pakistan Subcontinent. At Tandojam, West Pakistan the larvae have been found in large numbers on Aritolochia bracteata. The biology of this insect has been studied only by Ghosh (1914). The observations recorded by us concerning this species are given in the present paper. The work was under taken during 1962-63 at Tandojam.
Egg Description
The eggs of Polydorus aristolochiae are laid on the underside, very rarely on the upper surface, of host leaves. A high oviposition rate was observed in the months of August and September and again during March and April. Up to five eggs were collected from each leaf.
The chorion is covered with a reddish brown, soft gum like substance, in minute granular masses. The latter are arranged somewhat in undulating ridges meeting at a point. These give the egg the appearance of a citron with the long axis slightly shorter and a little inclined towards one side and never perpendicular to the leaf surface.
Incubation Period
Since the butterflies did not lay eggs in captivity, the incubation period was determined by recording the maximum period required for hatching of eggs collected in the field. The time taken for hatching of the eggs is given in Table 1.
Ghosh (1914) recorded that the incubation period is four to five days from June to September. The results obtained here are in general agreement with his observations. Between the months of October and March the incubation period is longer due to lower temperatures.
Larva
The larva is dark brown, and passes through four instars. The duration of larval stages was studied in the laboratory. The results are presented in Table 2.
It can be seen from table 2 that the duration of larval life varies from 14 to 62 days. The minimum duration was for larvae which hatched in September, 1962. Those hatching in the early part of January, 1963,
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Journal of the Lepidopterists' Society
Table 1. Incubation period of eggs of Polydorus aristolochiae
COLLECTED IN THE FIELD
|
Days re- |
Estimated |
Average |
|
|
quired for |
incubation |
monthly |
|
|
hatching |
period |
Temperature |
|
|
Month |
of eggs |
in days |
(Fahrenheit) |
|
September |
2-5 |
5 Days |
75.91 |
|
October |
3-9 |
9 Days |
69.64 |
|
November |
2-9 |
9 Days |
73.78 |
|
December |
2-9 |
13 Days |
60.88 |
|
January |
8-13 |
13 Days |
60.92 |
|
February |
4-10 |
10 Days |
69.92 |
|
March |
3-10 |
10 Days |
75.65 |
|
April |
2-6 |
6 Days |
83.75 |
passed their development during the two coldest months and, hence, their development required 62 days.
Ghosh (1914) has described the prolongation of larval life as hibernation. During our studies at Tandojam, however, larvae continued to feed during this period.
Pupa
The length of the pupal period varied from 10 to 230 days as is shown in Table 3.
The duration of the pupal stage is not correlated with atmospheric temperature (Table 1). Ghosh (1914) observed the pupal period to last from 10 to 303 days, and the present observations are in general agreement. However, Ghosh mentions that the insect undergoes a hibernation followed by an aestivation. This deduction does not seem to be correct since adult emergence took place in the coldest period as well as in hot months. Further, pupae from the same batch required widely varying
Table 2. Length of larval life of P. aristolochiae
Month in which egg hatched
Larval life (in days)
September
October
November
December
January
February
March
April
14-15 22-25 24-31 31-43 50-62 26-35 26-35 28-34
Volume 24, Number 1
21
Table 3. Pupal period of P. aristolochiae
Month in which Pupal period
larva pupated (in days)
August 10
September 13-230
October 13-228
November 19-150
December 36-141
January 44-143
February 14-179
March 13-172
April 12-38
periods before emergence of the adult, and it emergence by later pupating individuals sometimes occurred while from pupae of an earlier batch emergence of butterflies had not taken place. Thus, there is great range of individual variation in the pupal period, without apparent effect of temperature.
The above conclusion is corroborated by observations on pupae collected in the field. One hundred forty pupae were collected on November 5 and 25, 1962, from a small area at Tandojam which was under constant observation. Pupation had taken place on 5th and 25th November respectively.
Life Cycle
According to the observations made on the length of incubation, larval and pupal periods (Tables 1-3), it is seen that the butterfly
Table 4. Emergence of adults from field collected pupae
|
Date of |
Month of adult |
Pupal period |
|
collection |
emergence |
(in days) |
|
5 Nov. 1962 |
February |
88-115 |
|
March |
127-146 |
|
|
April |
153-176 |
|
|
May |
184-207 |
|
|
June |
215-224 |
|
|
July |
246-258 |
|
|
August |
275 |
|
|
25 Nov. 1962 |
December |
23 |
|
January |
51 |
|
|
February |
72 |
|
|
March |
120 |
|
|
April |
146 |
|
|
May |
166-176 |
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Journal of the Lepidopterists' Society
requires from one to about 9 months to complete its life cycle (exclusive of adult).
It may, therefore be concluded that the insect may have up to about 7 overlapping generations in a year. Normally, in the field it probably has fewer.
Field surveys revealed the presence of all the stages on the host plants throughout the year.
Natural Enemies
Thompson (1946) reported Apanteles aristolochiae Wlkn. as a parasite of this butterfly. No parasites of eggs or larvae were found during this study.
Acknowledgment
To Jerry A. Powell, University of California, Berkeley, we wish to express our sincere appreciation for correcting and improving the manuscript.
Literature Cited
Ghosh, C. C, 1914. Life histories of Indian Insects. V. Lepidoptera. Mem.
Dept. Agric. India, Ent. Ser. 5, 1: 53-58. Agric. Res. Inst., Delhi, Pusa. Thompson, W. R., 1946. Parasites of Lepidoptera (N-P). A catalogue of parasites
and predators, Sec. 1. Pt. 3. Imperial parasite service. Belleville, Ontario,
Canada.
A NEW CALL1THOMIA (ITHOMIIDAE) FROM BOLIVIA John H. Masters1
P.O. Box 7511, Saint Paul, Minnesota
During 1962-1965 I received several large consignments of Bolivian Ithomiidae from Franz Steinbach of Cochabamba, Bolivia. Perhaps the most interesting specimen among these is an unique and previously un-described Callithomia. The late Dr. Richard M. Fox, acknowledged expert in the Ithomiidae, examined this specimen, recognized it as a new species and intended eventually to describe it himself. With the death of Dr. Fox on April 28th, 1968, I have assumed the task of describing the insect and take pleasure in naming it after him.
1 Research Associate, Carnegie Museum, Pittsburgh, Pennsylvania.