Friday, December 9, 2011

Another new dragonfly family and basic dragonfly sex

Around the river here there has been a big dragonfly teasing me for awhile now. I spent several hours over the course of a couple weeks trying unsuccessfully to catch it or even just find it perching and see it well. I suspected it was a Neopetalid - a family of only one species: Neopetalia punctata. So yesterday I resolved to catch it and settle the issue - reserving the whole afternoon for the pursuit. Luck was on my side and immediately it flew by me and I netted it - all within 5 minutes. Upon catching it, I realized it was not the species I suspected, but another family entirely: Austropetaliidae - and quite a bit bigger than I initially realized (but still smaller than the Phenes raptor of the last post).

Hypopetalia pestilens, female, Chiloe Island
The family is restricted to only Chile and Australia, surely a remnant of the fact that these two land masses were once (oh so long ago) joined. There are a few other species in Chile, which I may be able to find in the upcoming weeks. It has been much talked about that the butterfly fauna of Chile is severely depauparate compared to similar areas (California is a good comparison in some ways), but it seems like the odonate fauna here is quite diverse. Interestingly, I have found that while butterflies are, by all standards, uncommon here - there are quite a few day-flying moths around, which is rare (but certainly not unknown: Cisseps and Ctenucha come immediately to mind) at home, perhaps using the vacant niches of butterflies as day-flying nectar feeders. I have even watched a few skippers tussling with the moths over territory.

Enough speculation: more pictures of the bug.

Hypopetalia pestilens, female, Chiloe Island

Hypopetalia pestilens, female, Chiloe Island
 How do I know this is a female? Odonates are among the easiest insects to determine sex as adults (orthoptera: crickets, katydids and grasshoppers are also simple). Take a look at the abdomen of the above:


See the little spike sticking out near the bottom of the end of the abdomen? That is the ovipositor, for laying eggs. Males have two sets of specialized sexual organs: claspers on the end of the abdomen for holding the female and on the second abdominal segment a "penis" that functions both to inseminate the female, but also to first remove the sperm of other males so that the maximum number of offspring will belong to him. Coupling of the sexes involves the male grabbing the female behind the head and the female bending her abdomen up to receive sperm, this position is called a mating wheel. Then the male generally oversees the laying of eggs, either by flying tight circles around the female while she lays eggs or by remaining attached, as seen here:

Nehelannia gracilis, male above, female below, Nantucket

5 comments:

  1. Hola.
    Desde hace un tiempo hemos visto a Hypopetalia pestilens en Bariloche, Argentina. Hay que recordar que los seres vivos no conocen de fronteras geográficas sino de fronteras ecológicas.
    Seguramente este insecto tenga una estrecha relación con el Bosque Andino Patagónico.
    Saludos.

    ReplyDelete
  2. Gracias para la observacion. Estoy completemente en acuerdo en la relacion con el bosque patagonico, yo solo encontre en un rio en el bosque, nunca en otros rios en el campo (con vacas/ovejas/casas).

    Un bonito bicho.

    Saludos!

    ReplyDelete
  3. Hola Eric
    Bonitas fotos para un insecto muy pocas veces fotografiado en la naturaleza. Estamos realizando una pequeña guía para el SAG y necesitamos fotografía de este odonato. ¿Sería posible que nos facilites una de las fotos para que aparezca en el libro?. En el libro saldría reconocido de quien es la fotografía.
    Para mas detalles por favor contactarme a alzure@gmail.com.
    Saludos

    ReplyDelete
  4. Hola Eric
    Bonitas fotos para un insecto muy pocas veces fotografiado en la naturaleza. Estamos realizando una pequeña guía para el SAG y necesitamos fotografía de este odonato. ¿Sería posible que nos facilites una de las fotos para que aparezca en el libro?. En el libro saldría reconocido de quien es la fotografía.
    Para mas detalles por favor contactarme a alzure@gmail.com.
    Saludos

    ReplyDelete
  5. This comment has been removed by the author.

    ReplyDelete