2019 desperate spring tipulid-chase

resting male

and female

Over the past few weeks, the annual swarm of giant brown tipulids has been (and still is) active in my yard; on the other hand, the Vanessa public garden swarms have nearly disappeared. Having finally armed myself with a red flashlight (most insects are unable or nearly unable to see it) and a somewhat decent slow-motion camera, I was quite impatient to collect some footage for the entomology outreach campaign.

I was rather startled to see the following thing one afternoon:

it was quite a surreal scene; swarm specimens would also occasionally cease their careful vegetation-colliding and literally bounce across the ground in a ridiculous, majestic fashion.



I wasted quite some time trying to film them.



After finally managing to align the phone camera with the fast-flying dipterans, I realized that the videos were still too blurred to be of much use for public campaigns; still, under slow motion the animals' seemingly senseless bumbling revealed a fascinating phenomenon.

From the beginning I had suspected that they were using their vast array of legs as pseudo-antennae; though they flied quite erratically when in the fenceside weed patch, they moved with a sense of purpose, as if carefully palpating the plants for suitability. Furthermore, they often also bounced against fences in an even more chaotic fashion, but did so even in the absence of lamps (contrary to popular belief, nocturnal insects' lamp bouncing is a highly abnormal stress-behavior). Upon video slowing, the tipulid flight patterns certainly appeared to support my antennation hypothesis:

(for some reason, ground bouncing usually occurred in straight lines or arcs, unlike wall bouncing)







Further attempts at flight video capture were wholly unsuccessful, although I did manage to capture several other things.

male and tenerally pale (I think) female

(unfortunately a planned timelapse on mating dynamics failed hilariously; during most of the filming period no additional males came, and after taking a long break I arrived just in time to see the female fly over the fence while still copulating)


Several other tipulomorph species were present, but these were not very abundant and I was barely able to observe any behaviors from them. EDIT: A while after the Large Brown swarming ceased, the first morphospecies became abundant for a few weeks. I have also seen wulpiana bouncing briefly on grass.

mottled sp. sitting on web

Nephrotoma wulpiana, a bright orange tipulid