Two new species of Indian stingless bees discovered from North-East India
Updated: Mar 5, 2021
By Basavaraj N. Hadimani
The tropics and subtropics are home to thousands of different types of bees. The bee group that frequently calls an observer’s attention is the stingless bees or Meliponini. Stingless bees are widely known in the Indian subcontinent as "dammar bees" (dammar is a resin from amongst dipterocarp trees), with additional local names, e.g., “putka” in Sikkim, “ngap siwor” and “ngap hamang” in Khasi language, “cherutheneecha” and “arakki” in Kerala.
Stingless bees are the oldest group of eusocial bees. However, we know very little about most stingless bee species, especially considering their ecological importance for the tropical ecosystem and when compared to honey bees and bumblebees. Like honey bees (Apini), stingless bees live in perennial colonies, have considerable caste differentiation between queens and workers, they build an elaborate nest that allows them to store large quantities of food and they use complex and interacting communication systems to coordinate their daily activities.
Species of stingless bees produce honey around 200-500 g per season. Honey is derived from stingless bees of high quality having medicinal value. On the other hand, stingless bees are effective pollinators of many of our economic crops of the families like Compositae, Cruciferae, and Leguminosae, etc. where honeybees fail to pollinate. Like many other animals, stingless bees face new challenges in an increasingly human-modified world, including large-scale habitat loss, the widespread use of agrochemicals, climate change and introduced species, all of which put pressure on stingless bee populations.
Stingless bees belong to the order Hymenoptera under the family Apidae, sub-family Apinae of Tribe Meliponini with more than 600 described species belong to 60 genera in the world. From India, 14 species of stingless bees were reported that are belong to three genera, namely Tetragonula Moure, 1961, Lisotrigona Moure, 1961 and Lepidotrigona Schwarz, 1939 of which Tetragonula is the most dominant with nine species, four species belong to Lisotrigona, and one to Lepidotrigona.
Most of the researchers in India concentrated only on stingless bee biology, morphometry, natural enemies, and pollination biology. However, the full diversity of stingless bees in the Indian subcontinent remains unknown because of the lack of more explorations in terms of taxonomic research.
A recent study from Dr. Shashidhar Viraktamath a renowned bee taxonomist from the University of Agricultural Sciences, Bangalore, and Dr. Rojeet Thangjam, Entomologist from Central Agricultural University, Imphal discovered two new species of stingless bees from northeast India, they came across two feral colonies, one in a mud wall cavity at Salema, Tripura, and the other in the soil at Kyrdemkulai, Meghalaya.
Samples of outgoing foraging bees from these two colonies were collected separately and a nest of both feral colonies was excavated to record the size of the entrance, length of the entrance tube, size of the nest cavity honey and pollen cells. The arrangement of the brood area, food stores, and waste dumping area was also studied.
Author’s described Tetragonula kyrdemkulaiensis Viraktamath and Rojeet, 2021 with associated females and males from Kyrdemkulai, Meghalaya and named the species after the place where it is collected. The male holotype with head, thorax, and metasoma dark brown to brownish black and all legs reddish-brown except trochanter and terminal four tarsal segments light brown, While female with head, thorax, and metasoma brownish-black to black and all legs brownish black except trochanters and terminal four tarsal segments ochraceous.
The authors have compared 34 morphometric parameters of female bees of T. kyrdemkulaiensis with the primary type specimens of Tetragonula from the Indian subcontinent. Values for 28 morphological parameters considerably larger in T. kyrdemkulaiensis compared to the values of morphometry of primary type specimens. They found subterranean nest of T. kyrdemkulaiensis in the soil at 90 cm depth with brood cells arranged in a cluster.
They also described another species, Tetragonula srikantanathi Viraktamath, 2021 based on females from Salema, Tripura. In this species, the female was identified by its morphometry, presence of dense plumose hairs on the face; distinct longitudinal bands of hairs on the mesoscutum and entire metasoma uniformly orange. This species was found nesting in mud wall vertically elongate cavity with unique single-cell thick layer of brood combs which has not been reported in any other Indian species of Tetragonula. The nest was divided into five areas arranged vertically from bottom to top viz, resin dump, food storage, brood, food storage, and resin dump. The brood area was in the middle of the nest cavity with honey and pollen storage both above and below the brood area. Authors have compared both species with the images and descriptions of primary type specimens of Tetragonula species occurring in the Indo-Malayan region and were found to be distinct in morphological characters, male genitalia, and nest structure.
They concluded that the genus Tetragonula includes several species complexes that are morphologically similar. Unfortunately, all the species reported from northeast India were based on morphometry and the color of worker bees. Until now no information is available on male bees of Tetragonula associated with females from this region. Hence, a systematic and exhaustive study on the diversity of stingless bees based on both male and female bees may result in the discovery of many more species from this hot spot region.
For further details, please follow the link: https://link.springer.com/article/10.2478/s11756-020-00662-0
Basavaraj N Hadimani, a Research Scholar at Division of Entomology, ICAR-IARI, New Delhi-110012, India.
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