The resin bee subgenus Ranthidiellum in Thailand (Megachilidae, Anthidiini): nesting biology, cleptoparasitism by Stelis, and new species

Abstract

Resin bees of the subgenus Ranthidiellum, are rare and endemic to Southeast Asia. These bees are known to construct resinous entrance tubes to their nests. Here, the new species Anthidiellum (R.) phuchongensissp. nov. is described along with a description of its nest collected from Phu Chong Na Yoy National Park, Ubon Ratchathani Province, Thailand. In addition, the bee cleptoparasite, Stelis (Malanthidium) flavofuscinularsp. nov., and the male of A. (R.) ignotum Engel, 2009, are described for the first time. A key to Ranthidiellum species is also provided.

A review of the anthidiine bees (Apoidea, Megachilidae) in Thailand

“…In morphology, the species is very close to Anthidiellum rufomaculatum (Cameron, 1902) with a minor difference in that the female holotype of “ Protoanthidium rufomaculatum ” [= Anthidiellum rufomaculatum , female from Kuching, Sarawak, Malaysia] has more minute paraocular marks, more slender marginal bands on its axilla and scutellum, and a reddish black translucent band present basally on the black integument of T1–T5. However, to confirm the status, there is no certain evidence that the males described by Pagden (1934) are the exact Anthidiellum apicepilosum , even though the locality of Bakit Kutu, Selangor, is adjacent to the Negeri Sembilan, where the female paratype was caught (further discussion in Nalinrachatakan et al 2021b ).…”

“…Male bee specimens were dissected for their genitalia and terminalia examination: i.e., using 3M KOH to clear out muscular artifacts and later preserved in glycerin (adapted from Gonzalez et al 2012 and Nalinrachatakan et al 2021b ). All terminology used follows Michener and Griswold (1994) , Michener et al (1994) , Michener (2007) , Engel (2009) , and Kasparek (2017) .…”

“…), and Stelis (1 sp.) ( Friese 1925 ; Cockerell 1929 ; Dover 1929 ; Pasteels 1980 ; Baker 1995 ; Engel 2009 ; Tadauchi and Tasen 2009 ; Niu et al 2019 ; Nalinrachatakan et al 2021b ). Nalinrachatakan et al (2021b) described two new species, one of Anthidiellum ( Ranthidiellum ) and another of Stelis ( Malanthidium ) , as well as documented their nesting biology.…”

The bee genus Anthidiellum in Vietnam: descriptions of five new species and the first male of Anthidiellum coronum (Hymenoptera, Megachilidae)

“…It can be separated from other genera by the following characteristics: body small, robust, metasoma oval-rounded, with strongly developed omaular carinae/lamellae, and an often-lamellate pronotal lobe ( Michener 2007 ). Species are frequently black, often with maculae laterally or with unbroken bands on the terga (see species of Ranthidiellum Pasteels: Engel 2009 ; Nalinrachatakan et al 2021 ). Additionally, the juxtantennal carinae are absent; the subantennal sulci are outwardly arcuate; the axillae are rounded, without a spine; the mesoscuto-mesoscutellar sulcus is broad; the mesoscutellum lacks lateral spines, but typically extends posteriorly as a broad, thin, truncate, or medially emarginate lamella overhanging the metanotum and propodeum; behind the propodeal spiracle there is a fovea, delimited by a carina, although sometimes the fovea is no larger than the spiracle; the jugal lobe of the hind wing is less than one-half as long as the vannal lobe; cu-v in the hind wing is less than one-half as long as 2M+Cu; the arolia are well developed; the mandible of the female has three or four teeth (tri- or quadridentate), while the male has two or three teeth (bi- or tridentate) ( Michener 2007 ).…”

“…Currently, the genus Anthidiellum comprises nearly 65 described species in seven subgenera, most of which are found in the Old World ( Pasteels 1972 ; Michener and Griswold 1994 ; Griswold 2001 ; Wu 2004 ; Michener 2007 ; Engel 2009 ; Niu et al 2016 ; Soh et al 2016 ; Kumar et al 2017 ; Nalinrachatakan et al 2021 ). There are about 30 species known from Asia, and about half of the species occur in Southeast Asia, all of which belong to the subgenera Clypanthidium Pasteels, Pycnanthidium Krombein, and Ranthidiellum Pasteels.…”