How do predatory hoverfly larvae find their prey?

A few days ago I was watching a hoverfly larva eat an aphid and that made me wonder how the predatory species even manage to find their prey? They’re basically just tubes with a digestive system but no discernible sensory organs.

When the larva was crawling, it sometimes moved its front end from side to side. Do they basically just feel their way around until they bump into something that’s edible?

4 Likes

Here is my observation of a hoverfly larvae and its prey from Gaborone Botswana. I got the impression that the suicidal prey were attracted to the larva, then climbed on it s back and very stupidly made their way to the head of the larvae to be an easy meal.

https://www.inaturalist.org/observations/66129975

I wonder if the hoverfly larva makes a chemical- a pheromone that attracts the prey and perhaps it would need a Chemist to check this out. it was interesting to see hoverfly larva carrying several prey insects for a free ride. perhaps it was just chance that they climbed on the back ! Do any real Biologists know what’s going on. Im just a Citizen non-Scientist with no biological training at all !

3 Likes

Welcome to the forum! I suspect it may be a combination of factors. The adults probably lay eggs in places where the larvae are more likely to find prey. The larvae probably use some combination of feel and smell. It varies between species. Some tachinid flies lay live larvae on plant stems, where they sit until something moves past them. They begin to sway, and if they contact something they latch on. If it’s not prey they will not penetrate it. If a moth larva gets knocked off the host plant, they will wander around waving their heads until they contact something. They are programmed to go up, so climb. If it smells and tastes right they eat it.
There has probably been some work done on this - it might be worth searching Google scholar for prey locating behaviour in fly larvae.
Adult - The Killer Fly Hunger Games: Target Size and Speed Predict Decision to Pursuit - FullText - Brain, Behavior and Evolution 2015, Vol. 86, No. 1 - Karger Publishers
I can’t find anything specific about larvae right now, but it’s probably worth a shot.

4 Likes

Eupeodes and Syrphus larvae are like little tigers. They rapidly move along the substrate. Eupeodes larvae rapidly and wildly swing their head around as they go so that it comes into contact with any potential prey nearby; they act like very aggressive but blind predators.

9 Likes

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=hoverfly+larvae+predation+sensory&btnG=

1 Like

That’s quite fascinating, and that larva looks awesome as well!

Oddly enough, the one that I watched eating also had an aphid sitting on its butt end. I wondered how it got there in the first place, but I couldn’t quite tell whether it was still alive or just a dead one that ended up stuck there somehow.

https://www.inaturalist.org/observations/95136803

2 Likes

Thank you! This specific link refers to both adult and larval feeding habits - Aphids-as-Crop-Pests20190628-30552-kq9e4b-with-cover-page-v2.pdf (d1wqtxts1xzle7.cloudfront.net).
Larval feeding is on p. 193.

1 Like

Thank you for your reply!

The ones that I watched definitely seemed to be “feeling around” for something every now and then, but it also could have been just to check the surroundings in a more general way. I was quite fascinated by how they’re even able to make sense of their surroundings and find their food.

1 Like

Neat! Thanks for pointing this one out, I think the ones I saw were E. balteatus larvae so this is exactly the kind of information I was looking for.

1 Like

Here in India, I found a species of hoverfly that use a plathopper eggs for their young one’s. https://www.inaturalist.org/observations/84667043
I shared a video link too. After few days I noticed the hopper you one’s never emerged and no trace of them. I could not record a young hoverfly pupate and emerge from it yet, but found a paper detailing such behavior http://www.informaticsjournals.in/index.php/jbc/article/download/3266/2349

2 Likes

This underscores that there is no certainty in Biology!

2 Likes

Based on the syrphid larvae I have observed in my yard. I believe the eggs were laid in areas with an aphid infestation. The larvae seemed to flail their head around until they found an aphid. In seconds, they sucked out the juicy parts, spit out the legs, then felt around for another. Because there were so many aphids, they did not need to hunt around for them during the time I was observing. It was entertaining though.

3 Likes

Welcome to the Forum!

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.