Dear entomologist colleagues, just wanted to find out if any of you have ever conducted and published on insect bioinventories without collecting insects? Is it defensible to do catch, ID and release type studies? Or photographic type observational studies? Or would you say that there is absolute no substitute to collecting?
For some insects (most orthoptera), you can study them acoustically. It is then possible to carry out counts by counting for example the number of singing males. The same is the case for most cicadas. The answer also depends on the geographic area concerned. In Europe, for example, almost all odonate species can be determined in the field and can then be released, but in tropical areas, to distinguish between certain species, collection is compulsory.
Yes, it is possible for some insect taxa. For example adult butterflies, Lepidoptera. The caracteristics that these insect taxa need to have for the entomologists to proceed a bioinventory would be: 1- diurnal (easy to be seen. 2- easy to identify to the species level using only their gross external morphology/color (for example it is almost impossible to do that with Diptera or Coleoptera). 3- possibility to distinguish between individuals to p[revent recounting of the same individual more than 1 time.
I prosose you to read:
https://assets.vlinderstichting.nl/docs/07e9597d-77c9-480c-afa8-4c5972f845d5.pdf
For some insects (most orthoptera), you can study them acoustically. It is then possible to carry out counts by counting for example the number of singing males. The same is the case for most cicadas. The answer also depends on the geographic area concerned. In Europe, for example, almost all odonate species can be determined in the field and can then be released, but in tropical areas, to distinguish between certain species, collection is compulsory.
Thanks Guillaume Doucet , that is fascinating. Never thought of that.
Agree with Guillaume Doucet and Jean-Jacques Itzhak Martinez Sir. But wherever possible you can leave them after sorting of external study. or if numbers are more in the study area then can be collected and preserved for further study or as a specimen.
Regards,
Dr. Vinaya Tari
Studying insects without collecting is useful in ecology : for monitoring populations (by example estimation of size of a pop with marks on the body of living specimens, killing biases the estimation).
The species must be easy to recognize in the land (Odonata, Orthoptera, Rhopalocera, some other groups, i. e. Hemipt. Pentatomidae, Hym. Sphecidae in north of France, Vespidae Vespinae [except in mountains], some wild bees and digger wasps, many Col. Cerambycidae, Col. Carabidae Carabini & Cicindelinae, maybe some Diptera species, etc).
For collecting and inventorying ground-dwelling insects, pitfall trap is the most effective. Malaise trap is one of the most widely used methods for recording insects in flight and for collecting large numbers of insects. Light traps are used for collecting nocturnal insects. Light traps particularly those that use UV light, as many insects are sensitive to UV light. Electronic insect traps utilize ultraviolet tubes to attract flying insects and trap them on a sticky glue board. These adhesive glue board traps attract flying insects by UV light to silently capture them on an adhesive board without killing them.
For Tiger beetles i guess it is impossible. There will always be collateral damage along the way :-)
I would rather say that just observing and photographing individuals is an exception and not a rule. At least, capture the individual, handle it gently, observe the specific characteristics, take a picture eventually and release it. Just very very few species can be observed in the environment and make sure of them.
They must meet certain conditions:
- Big specimens and easy observable;
- Very distinctive by other close species, typical in that environment;
- Very distinctive by other alien or new introduced sister species.
Please, in any case, please do not join the current of opinion, "do not collect", or "ecology can be achieved without species".
Non-killing identification would be very welcome: I have always thought how weird is that we have to destroy something that we want to study. Nevertheless, dead specimens in collections are essential because figures are not enough to understand the characteristics of a sp for example. Think about most descriptions from XIX or even XX century that are unuseful because describing a new sp only with words. Further, we have to face the collectionist problem, i.e. those people killing insects just to put in their collection as they collect stamps or postcards. Costs and benefits should be taken into exam when exploring a natural area, to understand what and how much to kill. Very difficult topic.
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