Szabolcs Sáfián who is doing a fantastic research work on African lepidoptera has just equipped some Charaxes castor in Liberia with a radio-transmitter.
It could be a fantastic tool to better understand some species behaviours !
They are currently in test on the common Charaxes castor, but they plan to do it soon on the rarer Papilio antimachus from which females are very hard to find and their behaviour and life cycle are badly known.
With miniaturization and GPS technologies, such tools can be the future of entomology to better understand behaviours, life cycle, migrations and so on.
Very interesting study. Usually this method is used in birds but I hardly believe it can be applicable to small butterflies! If they succeed in putting this small radio-transmitter on Papilio antimachus, it must be fantastic.
Looks like a rather long antenna on that transmitter? wonder how it will affect the butterflies ability to fly?
Charaxes castor is colloquially known as the "Giant Charaxes" for good reason: itss thorax is incredibly robust, and its strong stiff wings can reach a span of over 10cm (in the females). I've personally witness a Charaxes that was missing almost the entirety of it's hindwings flying around with little difficulty or impediment. Charaxes in general are incredibly tough, so I'd be surprised if this had much effect on the butterfly.
Compared with that man's fingers that Charaxes does not much look larger than most of its genus. If they are going to attach a transmitter to a male antimachus, they will be able to track its flight path but how will they find a female, because it eludes most staying up in the canopy. Unless they have a mini camera.
I just did a quick measurement of the width of the thorax of several of my Charaxes specimens. C. protoclea, C. etesipe, C. etheocles: ~4mm across C. zingha, C. candiope: ~5mm across (maybe 6mm on the C. candiope) C. brutus: ~7-8mm C. castor: ~9-10mm
Obviously a small sample size, but I think it gives a fair impression.
As for finding the females of P. antimachus... I'd think it would depend on the resolution of the readings. If their location data comes from fairly short time intervals, I'm guessing you'd start being able to make safe assumptions about behaviour, as I imagine flight behaviour would drastically change once the male is in copula. Gather enough data and, I'm speculating, you'd start to get a good idea of where the females might be hiding.
to follow a male of antimachus will tell you where it fly not what he is doing ! How to distinct a stop because of copula and one because of normal rest stop, how to distinct a slow fly because of presence of female and one because of feeding, etc. May be it will be possible to obtain different signature for different behaviour and to use more accessible species to obtain such signature.. lets see.
Anyway it is very interesting and it is a new way to investigate butterflies biology. Such experience can only be positive and bring new knowledeges.
Tom, a castor of 9-10 mm is quite a record and etheocles of 4 mm is probably the smallest butterfly in the world
You are right that castor is probably one of the most muscular butterflies in Africa and strongest flier. Charaxes behaviour is quite wel known, curious to see what this technic will add.
s'il n'y pas de solution c'est qu'il n'y a pas de problème ! akuna matata ....
May be it will be possible to obtain different signature for different behaviour and to use more accessible species to obtain such signature.. lets see.
Hmmm... I just read Observation of hill-topping behaviour by the Giant African Swallowtail It seems that a hilltopping male P. antimachus tends to patrol/circle around the same chosen spot and are fairly territorial. So, I imagine if you recorded a male circling a specific tall tree on a hilltop for a number of hours any deviation from that pattern (of sorts) would be significant... though I guess that wouldn't really help with locating females.
Apart from flight behaviour and how long a male survives, I am not sure what else they will discover. They will not be able to follow antimachus or a charaxes up into the canopy, and they are not going to find the early stages either.
Apart from flight behaviour and how long a male survives, I am not sure what else they will discover.
Maybe it falls under flight behaviour, but they'd probably learn the range a single specimen covers. I'd think that knowing how much area something like P. antimachus covers would help in establishing conservation areas for the species.
If I get the chance, I'll ask Safi what his aims are with this experiment.