grant burleigh's picture

Small flies on an iris leaf

Observed: 16th February 2013 By: grant burleighgrant burleigh’s reputation in Invertebratesgrant burleigh’s reputation in Invertebratesgrant burleigh’s reputation in Invertebratesgrant burleigh’s reputation in Invertebratesgrant burleigh’s reputation in Invertebrates
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flyiris
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Description:

Further to my post ”Small spider on tip of an iris leaf” (iSpot 18/02/2013), here are images of two small flies observed on the same leaf in the same recording session.

Identifications
Species interactions

No interactions present.

Comments

grant burleigh's picture

Small spiders- questions:

1: Are the small spiders under discussion in this set of posts part of some “Lilliputian” sub-habit in which the prey are also small – globular springtails, small flies etc.? These observations keep that possibility alive. 2: Accepting that the spiders are immature, do they eventually become much larger adults or are they “Peter Pan” spiders that never grow up? (A possibility I previously alluded to in a NaturePlus contribution: “Small spiders that patrol ivy"

Martin Harvey's picture

Lilliput

It's true that small predators often eat even smaller prey! E.g. some of the smaller ground beetles specialise in catching springtails.

Immature spiders, assuming they survive, will get larger and become adult; I'm not aware of spiders remaining as immatures for any longer than they would do normally. This can make identification more confusing, as the first question when looking at a small spider is whether it is a fully-grown small species or a juvenile of a larger one. If the males have developed their complex 'boxing-glove' shaped palps then you can be confident it is an adult, but both adult females and juveniles of both sexes have more slender finder-shaped palps.

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Entomologist and biological recorder

grant burleigh's picture

"?Peter Pans"

I was wondering if there was some sort of parallel here with certain springtails which I gather continue to moult after reaching "adult" size. I suppose you might rephrase that to say that, in this case, certain maturational properties are perhaps not yet complete when final observed size is attained.
I have yet to see larger versions of these small spiders. Perhaps they migrate to somewhere else. Alternatively, our site is quite shaded so perhaps there is not enough energy around for larger body size to develop.