Mouthparts today turtles tomorrow

This morning Kate and I set traps again in the Dairy Drainage to see if the diet of the turtles living there is changing as the season advances from spring to summer. If we are as successful as last month, I will not be posting for a couple of days.

Eight-spotted skimmer

Flame skimmer

In the meantime, I am spending today looking at the mouthparts of Odonates from a new group, the family Libellulidae. It includes the two dragonflies pictured here today, the Eight-spotted skimmer (Libellula forensis) and the Flame skimmer (Libellula saturate).

This is a frontal view of what prey see as a naiad labium of the Eight-spotted and Flame skimmers reaches out for them.

Ventral view of naiad showing labium.

Dorsal view of naiad showing wing buds.

This naiad scoops up its prey as it walks along. Note that the scoop has openings for water to pass through as it moves forward. Further, once the prey is in the scoop there are downward pointing hair-like projections to keep it in the scoop.

Side view of naiad showing major mouthparts.

The "scoop" showing with red arrows showing the hair-like projections that move outwards to hold prey in place.

Aeshnidae mouthparts.

Thus, Aeshnidae and Libellulidae, share the same ecosystem and but evolved so that they do not compete for the same food resource. This process began over 300 million years ago during the Carboniferous Period with Meganeura a dragonfly like insect with wingspans of up to 65cm (>2 feet).

Lastly, I invite you to ponder the problem animals like this face when we rapidly alter ecosystems. An apt analogy is the effects of hurricanes and volcanic eruptions on human cities and towns. The fact that we do this knowing we share the same ecosystem and depend on them is beginning to have some lasting effects on our species. Our ability to ignore this is fostered by "speciesism", a concept I will be touching on in the upcoming weeks.