JANS Journal of Applied and Natural Science 6 (1): 315-319 (2014) Ultramorphology of antennal sensilla of open-nesting honey bees Apis florea F. and Apis dorsata F. (Hymenoptera: Apidae) Neelima R. Kumar, Kalpna Nayyar, Ruchi Sharma and Anudeep* Department of Zoology, Panjab University, Chandigarh-160014, INDIA *Corresponding author. E- mail: anuresearch_aedes@yahoo.com Received: March 3, 2014; Revised received: May 30, 2014; Accepted: June 20, 2014 Abstract: Antenna of honey bees is geniculate and has been known to possess a wide variety of sensilla. The sensilla are sensitive to odor, temperature, humidity, air pressure and gustatory stimuli. In the present investigation, ultrastructural study on the antenna of the two open-nesting worker honey bees- Apis florea F. - the dwarf honey bee and A. dorsata F. - the giant honey showed considerable amount of variation in the types and distribution pattern of sensilla in the two species. The antennal form as well as the sensilla arrangement has been suggested to be adapted to the pheromone perception need of regarding a particular species. Keywords: Apis florea, Apis dorsata, Antenna, SEM, Sensilla INTRODUCTION South-East Asia is the centre of honey bee diversity and the evolutionary homeland of honey bees. Apis florea and A. dorsata are open-nesting bees which build single comb. The head appendages constitute an important morphological feature to study honey bee systematics. The antenna of honey bees is important for understanding behavior of honey bees. It consist of a basal scape, pivoted pedicel and a ten-segmented flagellum. Antennae are important for sensory perception. Various types of sensilla are observed on the segments of flagellum. According to Wigglesworth (1965), the antennae are the main sites of olfactory receptors in most insects. Six types of antennal sensilla have been observed on the flagellum of honey bee A. mellifera drone and worker. They have been referred to as a thick basiconic sensillum, a tapered basiconic sensillum, a trichoid sensillum, a placoid sensillum, a coeloconic or ampullaceal sensillum and a coelocapitular sensillum, formerly known as campaniform sensillum (Kuwabara and Takeda, 1956; Dietz and Humphreys, 1971). SEM studies on antennal sensilla of honey bee workers have been performed by Al-Ghamdi (2006) from Saudi Arabia. Suwannapong and Wongsiri (2004) described occurrence of sensilla trichodea types A, B, C and D on different segments of flagellum from Thailand. Therefore, the aim of the present study is to document the diversity of Apis species by using the scanning electron microscopic technique of an impor- tant morphological character i.e. the antenna. ISSN : 0974-9411 (Print), 2231-5209 (Online) All Rights Reserved © Applied and Natural Science Foundation www.ansfoundation.org MATERIALS AND METHODS Study material: Two open-nesting species- Apis florea F. and A. dorsata F. were taken for the present study. A. dorsata and A. florea are found wild in nature. A. dorsata contributes towards large amount of forest honey and bees wax harvested by tribal peo- ple of India. Study area and sample collection: A. florea was collected from nests located in a hedges and bushes in Panjab University Campus while A. dorsata was collected while foraging on flowers in Botanical garden, Panjab University, Chandigarh. Preservation: The collected material of Apis florea and Apis dorsata was preserved in 70% alcohol and the protocol of Bozolla and Russell (1999) was followed. Preparation of material for scanning electron microscopy: The antennae were carefully excised from the freshly collected worker bees of Apis florea and Apis dorsata. These were then washed with phosphate buffer. The samples were fixed in 5% gluteraldehyde for 2 hrs. Subsequently these were washed with phosphate buffer 2 to 3 times and then dehydrated through graded series of acetone and dried in a critical point drier. Dehydrated samples were mounted on slides in the desired orientation with the help of double side adhesive tape under binocular microscope. The samples were attached in such a way that they became visible from all sides. The stubs were placed inside the sputter for gold coating to overcome the problem of “charging” and “beam dam- age”. The sputtered specimens were examined in Jeol 2008 A P P L I E D A N D N AT U R A L S C IE N C E F O U N D A T I O N ANSF