Phylogeographic structure, outbreeding depression, and reluctant virgin oviposition in the bean thrips,Caliothrips fasciatus(Pergande) (Thysanoptera: Thripidae), in California

Abstract

Bean thrips, Caliothrips fasciatus, is native to western North America. Once considered a pest of several crops in its native area, its pest status has waned over recent decades. However, due to its habit of aggregating in the navel of navel oranges, bean thrips remains economically important because some countries importing oranges from California have designated it a quarantine pest. Despite continued propagule pressure, bean thrips has never established outside North America. We examined genetic variation in mitochondrial DNA among Californian populations of C. fasciatus and found that potentially two cryptic species are present (supported by Kimura 2-P distances): a common widespread form B and a rarer form A with a very limited distribution. Form B showed strong phylogeographic structure, with many haplotypes having a limited geographic distribution. Inter-population crossing experiments between three geographically isolated populations of form B resulted in the production of some female offspring, indicating a degree of compatibility between these populations of this haplodiploid species. However, substantial outbreeding depression was also detected. A low frequency of offspring production by hetero-population pairs was evidence of pre-mating isolation, while post-mating isolation was also evident in the elevated mortality of fertilized eggs in successful hetero-population crosses. One surprising finding was the total lack of offspring production by virgin females when isolated individually. However, virgin females did produce sons in the presence of other virgin females. A test for the presence of Wolbachia showed that form B was not infected, but that some populations of the rarer form A were.

Olfactory and physical manipulation by males on life‐history traits in Echinothrips americanus MORGAN 1913 (Thysanoptera: Thripidae)

“…The negative effect of courtship and male harassment on longevity, known from wolf spiders (Mappes, Alantalo, Kotiaho, & Parri, ), leaf beetles (Paukku & Kotiaho, ), dung beetles (Kotiaho & Simmons, ) and tsetse flies (Clutton‐Brock & Langley, ), was excluded. Presumably, a balance was formed between the negative effects (shown in the previous study by Krueger et al, ) and the positive effects of small aggregations of individuals (known from females of Caliothrips fasciatus Pergande , Rugman‐Jones et al, ) to the similar survival probability in this study.…”

“…Often, oviposition of virgin females in arrhenotokous species is lower than in mated ones (Li et al, ; Wrensch & Young, ). Virgin females of Caliothrips fasciatus stop egg‐laying when separated (Rugman‐Jones et al, ). But in contrast females held with dH 2 O (7) had the highest total fecundity and also a high oviposition rate.…”

Relationships among Caliothrips species (Thysanoptera: Panchaetothripinae) with one new species from Mexico

“…In the Sudan Gezira it was normal to grow cotton crops in rotation with Dolichos beans and, possibly as a result of this proximity, sudanensis adults commonly attacked seedling cotton (Bagnall & Cameron 1932). Similarly, other species that originally might have been associated with Fabaceae [fasciatus; phaseoli] also breed on many other plants (Rugman-Jones et al 2012). Moreover, tongi has been reported breeding on crops of Lactuca [Asteraceae] in Japan (Minoura & Masumoto 2016), although that is not likely to have been its original host.…”

Phylogeography of the Walnut Twig Beetle, Pityophthorus juglandis, the Vector of Thousand Cankers Disease in North American Walnut Trees

“…To this was added 120 μL of a 5% (w/v) suspension of Chelex 100 resin (Bio-Rad Laboratories, Hercules, CA, USA) and the reaction was incubated at 55°C for 1 h, followed by 10 min at 99°C. A section of the mitochondrial cytochrome oxidase c subunit 1 gene (COI) was amplified via PCR using primers and protocols detailed in [ 33 ], but with the inclusion of only 1 μL DNA template (concentration not determined). Following the discovery of highly divergent COI lineages (see Results ), we also amplified and sequenced a section of the conserved D2 domain of 28S rRNA (28SD2) from a small (N = 30) but representative number of specimens, using conserved forward (5'-CGTGTTGCTTGATAGTGCAGC-3') and reverse (5'-TTGGTCCGTGTTTCAAGACGGG-3') primers [ 34 , 35 ].…”