Written by: Thilina Hettiarachchi(1) and Robert Wrigley (2)
(1) University of Manitoba, 12 Dafoe Rd., Animal Science/Entomology Bldg., Winnipeg, MB, Canada R3T 2N2, thilinaphettiarachchi@gmail.com
(2) 505 Boreham Blvd., Winnipeg, MB, Canada R3P 0K2, robertwrigley@mts.net
Waiting impatiently through a long winter and the delayed spring of 2024, two entomological field guys could wait no longer to experience the great outdoors. And so, on a cold (7°C), windy, 6th of April, with patches of snow still lingering in protected sites, the two of us headed out to the Portage Sandhills, 18 km south of Portage la Prairie (49.800629, -98.217526; off Provincial Road 54N), with the weather office promising a sunny high of 15 degrees (never quite made it!). This is the site where Deanna Dodgson and Robert carried out their study of the Eastern Red-winged Blister Beetle, Tricrania sanguinipennis (Say, 1824), whose triungulin larvae attach to ground-nesting bees (e.g., Colletes inaequalis Say, 1837 and Colletes thoracicus Smith, 1853), and then devour the bee larvae in the bee burrows (Dodgson and Wrigley, 2022). Robert wanted to determine if the adult beetles had begun to emerge by this date, to compare with March 19, 2021 and April 28, 2022. Another potential challenge was whether the primitive road would be passable to the site, which had delayed our investigations in 2022.
Figure 1. Eastern Red-winged Blister Beetle, Tricrania sanguinipennis A. Dorsal view of female. B. Lateral view of female. C. Lateral view of male. D. A specimen struggling to rotate into its correct position.
Figure 2. A. A nymph of speckle-winged rangeland grasshopper, Arphia conspersa. B. Amara sp. C&D. Cuerna fenestella. E&F. Cuerna striata.
Figure 3. Thilina Hettiarachchi and Robert Wrigley (Left); Thilina with his camera equipment in the field (Right).
Figure 4. Patches of lingering snow at the sites.
Luck was with us because the road was mainly dry, and we discovered the first blister beetle within five minutes of arrival at a sandy blow-out. Barely able to crawl at 7°C (at 10:40 am), the specimen was difficult to photograph because it kept being tumbled over and over by the gusty wind. Recalling where the species had been abundant in past years along a nearby trail, we soon found dozens of specimens, most upside down and struggling to regain their feet in the wind, others crawling slowly over the sand. In past years, there was a high proportion of the population found dead in early spring, likely from being caught by freezing overnight temperatures and snow falls. The beetles have such limited locomotory powers and are flightless, it appears most are unable to dig or locate a burrow to pass the night. Among the 35 specimens we observed on the sandy trail, 10 were dead. It should be noted that the adults do not feed, and so must attempt to find a mate within their two-to-three week adult life stage. The risk of freezing and snow storms must be balanced with the benefit of having the beetle’s triungulin larvae active by the time their bee hosts emerge and commence mating in the subsequent few weeks.
Figure 5. A. Coccinella septempunctata. B. Tiger moth caterpillar. C&D. Formica bradleyi. E. Formica obscuripes. F. Lasius (Chthonolasius) sp.
Figure 6. A. Ellychnia corrusca. B. Wolf spider. C. Nabis americoferus. D. Euschistus sp. E. Pollenia sp. F. Sphragisticus nebulosus.
As the morning and early afternoon temperature crept up slowly to 14°C by 1:30, we observed the following:
- Family Acrididae: a nymph of Arphia conspersa Scudder, 1875
- Family Carabidae: Amara sp.
- Family Cicadellidae: Cuerna fenestella Hamilton, 1970, Cuerna striata (Walker, 1851)
- Family Coccinellidae: Coccinella septempunctata L.
- Family Erebidae: tiger moth caterpillars
- Family Formicidae: Formica bradleyi Wheeler, 1913, Formica obscuripes Forel, 1886, Lasius (Chthonolasius) sp.
- Family Lampyridae: Ellychnia corrusca L.
- Family Lycosidae: Undetermined
- Family Meloidae: Tricrania sanguinipennis (Say, 1824)
- Family Nabidae: Nabis americoferus Carayon, 1961
- Family Pentatomidae: Euschistus sp.
- Family Polleniidae: Pollenia sp.
- Family Rhyparochromidae: Sphragisticus nebulosus (Fallen, 1807)
Most of the above species were represented by only a few individuals, while the Seven-spotted Lady Beetle and the ants were abundant. Thilina was kept busy photographing, but again had to repeatedly chase down specimens tumbled by the wind. The accompanying photos attest to his persistence and skill. We also heard the calls of Sandhill Cranes and American Robins (both traditional signs of spring), and observed piles of woody droppings from Ruffed Grouse, foot prints and scats of Coyotes, prints of White-tailed Deer and Deer Mice, and abundant burrows of Northern Pocket Gophers. At two sites, deep excavations provided evidence that a Badger had unsuccessfully attempted to dig out pocket gophers.
At first having reservations whether our expedition might prove premature so early in the field season, the day proved quite worthwhile. Sometimes it pays to take a chance.
Acknowledgment
The authors express their gratitude to the contributors on the iNaturalist website who provided valuable assistance in identifying some of the insects here based on photographs.
References
Dodgson D and Wrigley RE. 2022. First record and ecological observations on the blister beetle Tricrania sanguinipennis (Say, 1824) (Coleoptera: Meloidae) in Manitoba. NatureNorth.com. http://www.naturenorth.com/spring/Blister_Beetle/Blister%20Beetle%20(Tricrania%20sanguinicollis)%20in%20Manitoba.pdf