Distribution of alfalfa weevil (Coleoptera: Curculionidae) and its parasitoids on the Canadian Prairies, with a key to described species of NearcticBathyplectes(Hymenoptera: Ichneumonidae)

Abstract

This study recorded distribution and size of alfalfa weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) populations in Saskatchewan, Canada, from 2001 to 2014. The spread of alfalfa weevil across the province, originally southwest to southeast, was northward and westward during this time. By 2014, only northwestern and west central areas remained relatively alfalfa weevil free. From a minor pest in 2001, the alfalfa weevil increased to be the principal insect pest of alfalfa (Medicago sativa Linnaeus; Fabaceae) in 2014. The parasitoid Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneumonidae) had a similar distribution. Other parasitoids collected included Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae) and Microctonus colesi Drea (Hymenoptera: Braconidae). Conservation of these parasitoids is an important step in maximising their effectiveness as alfalfa weevil biocontrol agents. Molecular sequencing of the DNA barcoding region of specimens identified morphologically as B. curculionis indicated moderately high levels of sequence divergence among specimens (up to 5.8%); however, interspecific genetic variation between other species of Bathyplectes Förster was also high. Therefore, we conclude that B. curculionis was the only Bathyplectes species collected in our study. An illustrated key to the described species of Bathyplectes in North America is provided, as well as DNA barcodes of most species, including five distinct barcodes in the Bathyplectes curculionis–B. exiguus (Gravenhorst) species complex.

Effects of Temperature and Relative Humidity on the Embryonic Development of Hypera postica Gyllenhal (Col.: Curculionidae)

“…Although, at low temperatures, very few eggs of H. postica hatched at humidity levels below 95% in a previous study [ 30 ], our results showed that nearly 50% of the eggs survived at a low RH regime. The differences between our results and others from North America or Middle East could be due to differences between regional populations [ 19 , 21 ], as has been reported when the influence of temperature in the postembryonic development of H. postica was studied [ 14 , 18 ].…”

“…Most of the studies regarding the temperature-dependent development of H. postica have been focused in larvae and pupae and have been carried out with populations from North America and Middle East Asia [ 14 , 18 ]. The results of these studies suggested wide variations in geographical regions [ 19 , 20 , 21 ]. On the other hand, literature dealing with the effect of abiotic factors on embryonic development is scarce.…”

Parasitism of the alfalfa weevil <em>Hypera postica</em> Gyllenhal by <em>Bathyplectes</em> sp. in Spain

“…Biological control against the alfalfa weevil with Bathyplectes sp. has been reported in several places of the New World [18][19][20][21]. However, no data from European literature are available.…”

Assessing species richness of the subfamily Campopleginae (Hymenoptera, Ichneumonidae) community in Darab damask rose rain-fed plain, Fars province, Iran

“…Campopleginae Förster is one of the most diverse subfamilies of this family, consisting of more than 2500 known species into 66 genera (Vas et al, 2022;Yu et al, 2016). Members of this subfamily are mainly solitary koinobiont parasitoids of Lepidoptera and less commonly Coleoptera larvae and may be known as promising biological control candidates for some agricultural pests (Quicke, 2015;Scaramozzino et al, 2018;Shaw et al, 2016;Abedi et al, 2020;Bagheri et al, 2020;Di Giovanni et al, 2021;Soroka et al, 2020). One of the most important biological characteristics of campoplegines is that they are polyphagous in their host range because of the injection of polydnaviruses along with their eggs which help them to feed on a broad spectrum of Lepidoptera species (Shaw et al, 2016;Stireman & Shaw, 2022).…”