Dasymutilla vesta vesta    




habitat
Arid sandy regions.

seasonality
In Alberta, specimens have been collected from April to September. Adults have been observed into October (Hennessy 2002).

identification
These wasps are antlike in appearance (Manley and Pitts 2002). Compound eyes somewhat hemispherical. Felt line only present on tergite II. Females: 5.5-13.5 mm and wingless (Williamset. al., 2012). Setae not plumose (Manley and Pitts 2002). Head and mesosomal integument varies from pale orange to red (Williamset. al. 2012). Antennal scrobe, carinategena, and posterolateral head tubercles lacking (Manley and Pitts 2007). Elongate mesosoma with a narrow scutellar scale and no transverse carinae anterior to it (Manley and Pitts 2007; Williamset. al., 2012). Propodeum with small pits or fine grooves and only a few setae posteriorly. Males: 7.5-14.5 mm and winged (Williamset. al., 2012). Tergum and sternum II have reddish-brown setae (Manley and Pitts 2007). Black setae on Tergites 3 to 7 (Williams et. al.,2012). Mandibles lack notches ventrally (Manley and Pitts 2002) and sternum II lacks median pit (Manley and Pitts 2007). Wing venation normal with a sclerotized pterostigma (Manley and Pitts 2002). Coarsely pitted tegulae (Williamset. al., 2012). Mesonotum is broadened and elevated. Axilla prominent and notauli absent (Manley and Pitts 2002). Two spurs are present on the mesotibia. Pygidium has a fringe of setae at the apex (Manley and Pitts 2007).

life history
Solitary ectoparasites of ground-dwelling wasps and bees (Mickel 1928). Adult females enter nests and deposit eggs into diapausing larvae or pupae (Arneson and Pitts 2003). The parasitic larvae then consume the entire host before entering the prepupal stage (Mickel 1928). The size of adults is believed to depend directly on the size of the host larva. Thus, host availability may be the cause of geographic size differences (Deyrup and Manley 1986). Also, females may determine whether to release or withhold sperm upon oviposition depending on host size. As they search for hosts, adult females build new retreats daily (VanderSal 2008). Females have up to four emergence periods per year, each lasting between five and ten days (Hennessy 2002). Male abundance follows closely. Activity of female generations may overlap, attributed to a secondary host search. Males may also be found between emergences. Mandible abrasion has been used to estimate emergence date in females. Consistent wear throughout generations implies a digging behaviour performed by all females. Adults are inactive midday when temperatures are highest; however, females have a higher tolerance to high temperatures than males (Mickel 1928). This is likely due to their reduced mobility. Many females overwinter and may have a lifespan of over ten months (Hennessy 2002). Males have shorter lifespans. Adult females arereputed to have a very painful sting (Mickel 1928).

conservation
Not currently of any concern.

diet info
Currently known larval hosts: Bembix cinerea Handlirsch, Trypoxylon politum (Say) (=albitarse Fabricius), Nomia melanderi melanderi Cockerell (Williams, et. al., 2012), and Trypargilum politum (Say) (Manley and Pitts 2007). It is speculated that adult females eat nectar and larvae from host nests (Brothers 1989).

range
In Canada, found in southern Alberta and BC. In the US, nearly transcontinental, but not reaching the West coast. Recorded from Tamaulipas in Mexico (Williams, et. al., 2012).

notes
Information is somewhat limited on Dasymutilla species. Sex association is challenging due to sexual dimorphism and differences in geographic ranges between conspecific males and females. The wide geographical range and variation within Dasymutilla vesta vesta has resulted in many synonymies (Manley and Pitts 2007). The brief nature of mating in this group reinforces this challenge by making it difficult to find copulating pairs (Williamset. al., 2011). Another challenge is the study of larval hosts which requires digging up host nests for identification (Hennessy 2002). Considering the variability in size of this species as well as its geographic range, it is very likely that many larval host species remain undiscovered (Williams, et. al., 2012). According to Mickel (1928), the type specimen for Dasymutilla vesta vesta is a female from Colorado territory and is located in the collection of the American Entomological Society of Philadelphia.

people
species page authorWingert, B.2013 

quick link
http://entomology.museums.ualberta.ca/searching_species_details.php?s=39066

 

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