Existence of two strains of Habrobracon hebetor (Hymenoptera: Braconidae): a complex in Thailand and Japan

Abstract

Habrobracon hebetor Say (Hymenoptera: Braconidae) is a cosmopolitan gregarious ectoparasitoid that attacks larvae of several species of Lepidoptera. Although there are two genetically different strains within H. hebetor, distribution of the strains has been poorly understood. In 2010, in Thailand, where H. hebetor has been known as a parasitoid of stored grain pests, it was found that H. hebetor attacked Opisina arenosella Walker (Lepidoptera: Oecophoridae), which is an invasive pest of coconut palm. For correct identification of this H. hebetor, we conducted DNA analysis and cross tests using populations collected from O. arenosella and stored grain pests in Thailand and populations in Japan known as H. hebetor. We obtained 413 bp of mitochondrial cytochrome oxidase I (COI) sequences and 414 bp of 16S rRNA gene sequences, and both indicated that there are two distinct clades within H. hebetor: one contains insects from Thailand, Spain, India, and Barbados; the other contains insects from Japan and the USA. There were no genetic differences or sexual isolation between Thai populations from different hosts. Our results also showed that populations in Thailand were sexually isolated from a H. hebetor population in Japan.

Patterns and drivers of genetic diversity and structure in the biological control parasitoidHabrobracon hebetorin Niger

“…Based on microsatellite loci, Iran and Niger H. hebetor were again clearly separated into two strongly differentiated populations ( F st−ENA( Niger vs Iran) > 0.44). The extent to which all genetic parameters differed led us to wonder whether the two lineages were distinct morphocryptic entities of H. hebetor, possibly geographically associated as reported by Chomphukhiao & co-authors (2018) or even two closely related species although both clustered with H. hebetor sequences. This question remains unanswered until additional samples from Iran can be analyzed.…”

Polyphagous koinobiosis: the biology and biocontrol potential of a braconid endoparasitoid of exophytic caterpillars

“…xylostella (Arvanitakis et al 2014). On the other hand, recent studies have revealed that the host ranges of idiobiont ectoparasitoids, such as Bracon and Habrobracon species (Braconidae), are narrower than that expected previously (Chomphukhiao et al 2018;Matsuo et al 2016). Host specificity of parasitoids in relation to koinobiosis or idiobiosis will be a challenging issue to be discussed again.…”

Revalidation of Habrobracon brevicornis stat. rest. (Hymenoptera: Braconidae) Based on the CO1, 16S, and 28S Gene Fragments

“…The best characters to discriminate the two species are therefore the ones given in the key: length of antenna to length of head and mesosoma; orientation and length of seta of vertex; length of first flagellar segment of male antenna to length of second flagellar segment; suface structure of metasoma. Chomphukhiao et al (2018) tested for reproductive success and it showed that the two populations (Japan and Thailand) or in other words the two species H. hebetor and H. brevicornis did not reproduce or only produced males. They confirmed the results of Heimpel et al, that the cryptic species aka H. brevicornis is sexually isolated from H. hebetor.…”

“…Although H. hebetor and H. brevicornis do perform differently as biological control agents depending on the host. For example, according to Chomphukhiao et al (2018) both species H. hebetor and H. brevicornis attack Corcyra cephalonica and P. interpunctella (Pyralidae), however, H. brevicornis seemed to lay more eggs with a higher adult emergence rate. This confirms the observation of Heimpel et al that that the cryptic species aka H. brevicornis produces more eggs.…”

“…Heimpel et al (1997) have mentioned, that there is a cryptic species among H. hebetor, which is sexually isolated and has different biologic traits. At the same time, Habrobracon brevicornis Wesmael 1838 has been suspected to form a valid species and not a synonym of H. hebetor, but it has not been verified yet (Chomphukhiao et al, 2018;Quicke, 2015), although some authors have treated it as a separate species (Haider et al, 2004;van Achterberg, 2014;van Achterberg & Polaszek, 1996). H. hebetor and H. brevicornis have been formally synonymised by Puttarudriaha & Basavannaa (1956), and then this synonymy has been subsequently used by many authors (Papp, 2012;Tobias, 1986).…”