Erebidae – Erebinae

LIST OF CARESHEETS/SPECIES INFO: (Click on the names)

Thyas juno 

Erebinae the wild
The “true erebid moths” or Erebinae is a (sub)family and/or group of moths that consists of about 10.000 described species.  Before a taxonomic revision that included new groups such as the Lymantriinae (Lymantriidae) and Arctiinae (Arctiidae) – the tussock and tiger moths, they were considered to be the only and one true types of ‘Erebid’ moths. True true erebid moths, Erebinae, can be found all over the world. Among them are the largest species of moths ever recorded such as the white witch (Thysania agrippina) with 320mm+ wingspan and other species of the “witch moths” group such as the black witch (Ascalapha odorata) and others that have wingspans over 150mm.

There are several remarkable traits found in this group. One of them are the piercing and sucking mouthparts. While the proboscis itself is nothing new, the Erebinae have evolved to use them in unconventional ways – in many species, the tip of the proboscis is hardened and almost “saw” like, allowing them to penetrate surfaces that other moths can not with their soft mouth parts. A famous example are the fruit piercing moths (genus Eudocima) that, as their name implies, use their sharp proboscides to pierce fruits and penetrate deeply into them, allowing them to suck the suices from them. While many types of moths are fructivorous, Eudocima is one of the few species that does not have to rely on fallen or rotten fruits. It is also not much of a suprise that the vampire moth (Calyptra thalictri), one of the few moth species on earth that actually drink blood, is an Erebinae. Since many Erebinae already developed sharp piercing mouth parts for various purposes, switching to drinking blood was the next logical evolutionary step – genus Calyptra uses it to pierce the skin of mammals. These and more interesting reports, including a moth that drinks the tears from the eyes of sleeping birds (Gorgone macarea), illustrate the unusual ways Erebinae can feed.

Erebinae moths are also among the moths with the longest lifespans – this is likely the reason they have evolved such sophisticated and elaborate feeding methods and mouthparts. Most species have the potential to become several months old. Their diet varies from species to species, but like most other Lepidoptera, they can only consume liquids with their proboscis. Erebinae moths survive on a diet of sugar rich substances such as tree sap or fruit juice. Interestingly, to my knowledge, there are no flower visiting species that feed on nectar or visit flowers – and if there are, they must be rare. The reason for this could be that Erebinae find their food mainly by smell, not vision (an important factor for locating flowers) and are attracted by volatile compounds released from fermenting, rotting fruit or tree sap (such as volatile acids and alcohols) that are not present in flowers. In wild observations Erebinae are often strongly attracted to bait traps with wine, beer, or fermenting fruits. Enabled by their long lifespans, constant need to find food sources and survivability, Erebinae are generally strong fliers that have quite active lifestyles and can migrate large distances – in some cases thousands of kilometres (Thysania sp., Ascalapha sp.).

It is a broad generalisation to say that all Erebinae have brightly coloured hindwings, but it seems to be a common theme in this family. Especially the species that fold their forewings over their hindwings in the resting position, tend to have very well-camouflaged forewings resembling a leaf or tree bark, but have very brightly coloured hindwings that they can suddenly reveal to scare away potential predators. This has given some groups of Erebinae (such as genus Catocala) the common name ‘underwing moths’: because the hindwings are contrasting and bright compared to the otherwise drab and well camouflaged animal. These hindwings come in a great variety of colours: from bright red, to pink, orange, yellow, black and white (Catocala sp.) to extremely bright pink (Miniodes sp.) or  bright iridescent blues (Ischyja sp.) – the colour intensity of these moths can be quite suprising and breathtaking.  Many species however have lost their ‘flash-colours’ and are overall grey or brown. Some species that rest with their wings spread out revealing the hindwings (thus nullifying the suprise effect of the suddenly revealed hindwings), have these warning colours on the underside of their wings instead of their hindwings. When disturbed or molested, many species will drop to the floor and flop around while rapidly flashing the wings.

During the day, most noctural Erebinae moths hide themselves well and are difficult to find. They seek deep crawling spaces or crevices to hide into and may be encountered in caves, bird nest boxes, hollow trees, basements, between tree bark, stacks of old rotting wood, garden sheds, under bridges and more places. It is not uncommon to encounter multiple individuals of the same species hiding in the same place, a behaviour known as ‘roosting’. By gathering in groups and resting together in a high density, this behaviour aids their individual chances of survival, camouflage, and most importantly thermoregulation (when the bodies of multiple moths are close together, more warmth is retained) and this behaviour may thus be more common during cold nights.

Erebinae  in captivity
Erebinae are rarely being bred in captivity. Rarely, but not never, since there are a few experts that had succes with a wide range of species. But expertise on this subject is very rare. The reason is because Erebinae are some of the most difficult moths to breed in and take care of captivity. The moths have very long lifespans in some cases and can live for many months and require to be fed as adults on a constant basis. They are fructivorous and require a more expensive diet of fermenting fruits or sugar/alcohols. They are also very active at night and may fly large distances; this requires a reasonable amount of space for them to fly, since these long lives moths may batter their wings against the cage walls and damage fast, shortening their lives. Last but not least, some Erebinae are very picky about pairing and oviposition. While some families of moths will swiftly pair if they find another male or female, Erebinae can have more complicated habits, and may have specific requirements in regards to space, temperature, lighting and so on. Some large and especially tropical species have never been bred in captivity despite constant efforts. This indicates that their needs, behaviours, pairing rituals and ecology are much more complicated than most other moth families as imagoes and perhaps not well understood. Some species are also very picky about where they lay their eggs. Because of their long lifespans, they can permit themselves to be more choosy  about the place where they decide to lay eggs; some species only seek their specific host plants and will, much like butterflies, refuse to lay eggs in its absence. Some species go even further and only lay on certain parts of the plant (buds, stems, flowers). All these factors combined is what makes many Erebinae unbreedable.

Despite this there is also some good news. A few species still do very well in captivity. In particular many palearctic Erebinae can be bred for multiple generations with some practice. In particular, most species from the genus Catocala (250+ species) are perfectly breedable in captivity, and a few experts and collectors have taken to breeding them. Other successes include Ophiusia species, Thyas juno, and a few more. But because of their complicated life cycles and demanding biology as adults and larvae, Erebinae will most likely remain obscure – and as with the majority of species – regarded as impossible to breed in captivity.

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