Morphology and Anatomy of Some Fireflies (Coleoptera: Lampyridae) of Bangladesh

Abstract

Morphology and anatomy of five species of firefly (Lucio/a chinensis, L. ova/is, L. sp., Diaphones sp. and Lamprigera sp.) of Bangladesh have been investigated in the present study. Of these Lucio/a chinensis, L. ova/is and L. sp. is under the subfamily, Luciolinae; Diaphanes sp. and Lamprigera sp. are under the subfamily, Lampyrinae. During the year, 1998-2004, regular samples of firefly were collected. Concentration of work has been mostly given on adult fireflies. Investigation on the larva of Lamprigera sp. was also conducted. Female of Lamprigera sp. and Diaphanes sp. we’re not available for investigation. The external morphology and the digestive system, nervous system and reproductive system are described. None of the species were collected during the daytime. Most of the samples were collected within three hours of sunset. In late night only few specimens were found. The three species, Lucio/a chinensis, L. ova/is, and L. sp. were very common in April to August. In same ecological habitat two species were seldom encountered at the same time. Lamprigera sp. were found in July, but very few in number, whereas a number of Lamprigera larvae were found in April to June. Diaphanes sp. were common at winter i.e., from November to January. Among the five species of firefly, Lamprigera sp. was the largest, (19.45-21.25 mm) and the smallest one was L. sp., (5.38- 5.52mm). The main feature of sexual dimorphism is their light organ. Luminescence organ in male is located on two ventrites (sixth and seventh) whereas that in female is located on only one abdominal segment (sixth). All the species investigated were alate. However, only one larviform female Diaphanes sp. was found, but results of the finding could not be depicted in the present dissertation. Perhaps there is a relationship between the body length and the alimentary canal, and the ratio of body length and alimentary canal is related with the nature of the food. In the present investigation, the ratio of body length and alimentary canal for male specimen is 1: 1.3 in Lucio/a chinensis, 1.3: 1 in L. ova/is, 1: 2.8 in L. sp. and 1: 1.6 in Diaphanes sp. In case of female Lucio la chinensis, the ratio is 1: 2, in L. ova/is 1. 1: 1 and in L. sp. 1: 3 .2. Alimentary canal was longer in female than that of the male specimens. That means the feeding habit of male and female might be different. In all cases, four long transparent Malpighian tubules were found. They were cryptonephric types. Malpighian tubules of Lucio/a chinensis were broader while the Malpighian tubules were longer and convoluted but narrower in case of L. ova/is and L. sp. In all investigated species of fireflies, the first abdominal ganglion was fully and the second abdominal ganglion was partially fused with the metathoracic ganglion. In three Lucio/a species, only four discrete abdominal ganglia (third, fourth, fifth and sixth) were found, whereas the seventh and the eighth abdominal ganglia were fused. In case of Diaphanes sp., the number of discrete abdominal ganglia was six i.e., ganglia 3 to 8 are all discrete. Testes were cluster shaped. The number of testicular follicles varied from 8 (both in Lucio/a sp. and in Diaphanes sp.) to 18 (in Lucio/a chinensis). Three pairs of accessory glands were detected in all the observed three species of Lucio/a, but none was found in Diaphanes sp. The number of ovariole varied from 8 (in L. sp.) to 25 (in L. ova/is). The number of ovariole and testicular follicle was same in L. sp. i.e., 8. In all species a prominent, well-developed spermatheca was found with a spermathecal gland and an accessory gland with some variation in its shape. In L. sp. the accessory gland was a small knob-like structure, but in L. chinensis and in L. ova/is, the gland was branched and much prominent. The work has been conducted in the Integrated Pest Management Laboratory of the Institute of Biological Sciences of Rajshahi University.