16/11/23 Photos 1-2 - Raise 1, adult specimen
21/11/23 Photos 3-4 - Raise 2, adult specimens frozen for future study
The raising of Epimarptid moths, seemingly the first iNaturalist observations in Australia.
Recently I've become interested in Gelechioidea, whose caterpillars are typically small, unknown, and in desperate need of rearing. Larval behavior varies greatly in this superfamily, with case-bearers in the Hemibela genus to Pyroderces terminella which has been reported feeding on spider eggs (Common & Slater 1990).
However, sometimes a caterpillar can be found feeding on a simple garden weed, as is the case here. These Epimarptid moths (species unidentified) were discovered on the annoying garden weed, Commelina diffusa, in which the caterpillars fed beneath strange silky shelters until the vine's leaves are completely skeletonized.
09/11/23 Photos 5-6 - Caterpillar outside of silk shelter
08/11/23 Photos 7-10 - Silk shelters created by caterpillars
As you can see, the caterpillars are very small (~2mm), along with their silk shelters (~2mm-1cm). The strange tear-drop shaped silk shelters were always positioned in the centre of the leaf, with the shelter growing into a large shapeless mass as the caterpillar develops. Leaf damage was typically seen around the shelter, rather than beneath it, so perhaps the caterpillars stuck their heads out of the shelter to feed.
08/11/23 Photos 11-12 - Cocoons made by caterpillars
Though I attempted to raise the species from its larval stage, in captivity the caterpillars left their silk shelters and refused to feed on the leaves (as seen in photos 5-6). I instead resorted to finding a pupa and bringing it into captivity instead.
The cocoons are tube-shaped structures with surrounding silk and leaf eaten away. The cocoons were positioned on the opposite side of the leaf to the original silk shelter. It took about 8 days for the cocoon in photos 11-12 to hatch.
After the first successful hatching (photos 1-2), I took more cocoons into captivity, and froze the moths which hatched out for future taxonomic study (photos 3-4).
16/11/23 Photos 13-14 - Cocoons collected for collecting and freezing of moths
It is indeed possible for two caterpillars to feed on the same leaf, forming separate silk shelters as seen in photos 7-8. Likewise, the cocoons collected for specimen freezing were found side by side.
03/11/23 Photos 15-16 - Commelina diffusa, hostplant of raise 1 specimens
30/10/23 Photos 17-18 - Commelina sp., hostplant of raise 2 specimens
The Commelina vines in which the caterpillars fed have been reaping havoc in our garden, climbing over other plants and forming dense vine thickets. With the large amount of this vine, there is an equally large amount of these caterpillars, so if the frozen specimens become damaged in some way (unlikely), I can at least collect more.
Will continue to rear caterpillars in the future.
*To be clear, I do not like killing specimens, and only do so when they are of importance or needed for study.
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References
Common, IFB, Slater, Ederic 1990, Moths of Australia, Melbourne University Press, Carlton.
Further reading on Epimarptidae if interested:
Kim, S Lee, S 2016, 'First record of family Epimarptidae Meyrick (Lepidoptera: Gelechioidea) from Korea, with newly recorded species', Journal of Asia-Pacific Biodiversity, vol. 9, no. 4.
08-21/11/23 - Epimarptidae sp., hostplant: Commelina spp.
QLD:WET