Archivos de diario de julio 2020

01 de julio de 2020

Eastern Pondhawks

I've often speculated about the ferociousness of Eastern Pondhawks (erythemis simplicicollis), and was reminded of that again recently when I saw two individuals, one male and one female, devouring Banded Pennants (Celithemis fasciata). When I looked at my contributions to the Odonata-predation project on iNat, of the 46 observations submitted, 17 were of this species, broken down on these lines:
Female-12
Male-5
Other odes as prey-9 (females were the perpetrator in 8 of these, including one eating another Eastern Pondhawk)

The abundance of this species partially explains the high percentage of observations, but prey choices probably play a role as well. For example, Common Whitetails (Plathemis lydia) are of similar abundance, but I have never seen one eating anything. Presumably they're typical prey items are so small that they are caught and dispatched quickly enough to escape observation. Large clubtails often capture large prey items, but Dragonhunters (Hagenius brevistylus) are the only other species I've seen consistently preying on other odes. Arrowhead Spiketails (Cordulegaster obliqua) also capture large prey, Gray Petaltails (Tachopteryx thoreyi) seem to specialize in large butterflies. Most fliers (darners, etc.) appear to prefer smaller prey, though I have twice seen Common Green Darners (Anax junius) capture large odes, Twelve-Spotted Skimmer (Libelulla pulchella) and Eastern Pondhawk. There is also an iNat observation from Oklahoma of a Cyrano Darner (Nasiaeschna pentacantha) devouring a Flag-Tailed Spinyleg (Dromogomphus spoliatus), and another report from a reliable source of another Cyrano capturing a Swift River Cruiser (Macromia illinoiensis). On a smaller scale, I've only seen two damselflies preying on other odes: a Rambur's Forktail (Ischnura ramburii) eating a Stream Bluet (Enallagma exsulans), and a Great Spreadwing (Archilestes grandis) with a Familiar Bluet (Enallagma civile).

Ferocity is not scientifically measurable, but if it were, Eastern Pondhawks, centimeter for centimeter, would rank at or near the top of that scale.

Publicado el julio 1, 2020 12:14 MAÑANA por arrowheadspiketail58 arrowheadspiketail58 | 2 observaciones | 0 comentarios | Deja un comentario