DISTRIBUTION:

Antheraea larissa ridlyi (wingspan: males: 124-150-166mm (BG); females: 170mm // fwl: males: 75-85mm; females: 85-90mm) flies in
Burma = Myanmar;
Thailand: Trang;
Peninsular Malaysia: Cameron-Highlands; Kuala Tahan;
Borneo: Sarawalk;
Sumatra: Kotapinang, Gn. Malayu, Sindar Raya, Langkat, Aek Tarum, Prapat, Huta Padang, Sarolungan, Bukit Subang, ENE Padang, Air Sirah, Lampung: E. Liwa at elevations from sea level to 1300m.

I believe A. larissa ridlyi also flies in Cambodia, based on the Bill Garthe image below. This subspecies seems to have the males with the most oblique forewing outer margin, although the male from Cambodia appears quite extreme in that regard.

Antheraea larissa ridlyi ?? male, Cambodia, 166mm, courtesy of Bill Garthe.

Antheraea larissa ridlyi male, Sumatra,
courtesy of Eric Van Schayck.

Those specimens from Palawan, Philippines: are A. larissa palawarissa.

Visit Antheraea larissa larissa Subgroup Comparison Plate.

"In a recent publication (Paukstadt, U., Paukstadt, L.H., & Brosch, U. (2000): Taxonomische Änderungen bei den Taxa des Antheraea-larissa-Komplexes (Lepidoptera: Saturniidae). — Entomol. Z. 110 (3): 71–72) U. Paukstadt et al. published the opinion that a) the Philippine (except Palawan) larissa should belong to a separate species, mindoroensis, with two subspecies (mindoroensis and philippirissa), and b) the Javanese and Neomalayan populations of larissa should belong to two different subspecies, larissa (on Java/Bali) and ridleyi (other area). The publication did not supply any illustrations nor detailed descriptions nor a reliable diagnosis to prove that opinion. Based on the little data delivered within that paper we cannot adopt this hypothesis. The variability both in genitalia morphology and in wing pattern and colouration is so high under the different insular populations of larissa s.l. that we still believe that it cannot be proven on the morphological basis alone that the Philippine and the Sundanian larissa belong to different species. Therefore, we prefer to deal with the Philippine populations as subspecies of larissa for the time being (as published by us in 1998). In addition, we do have some doubt that it really was justified to separate ridleyi from larissa; in contrast to other Javanese Saturniidae and Brahmaeidae the differences in the “larissa-complex” between Java and Neomalaya are only minor. — In any case, it might well be possible that there are genetically fixed relevant (i.e., of subspecific of specific rank) differences between some of the insular populations of the “species-complex” of larissa; but we think that this cannot be shown with external and genitalia morphology of such variable taxa alone; this can only be demonstrated reliably by biochemical or genetical studies." Nassig Commentary

I live in an area (Montague, Prince Edward Island, Canada) where there are healthy populations of both Hyalophora cecropia and Hyalophora columbia. I have reared thousands of larvae of both species over the years and I overwinter breeding stock and also operate lights to call in gravid females of all local Saturniidae and Sphingidae. I have personally taken male and female wild/natural hybrids of the two Hyalophora at my lights. The hybrid females look like large columbia, but carry no developed eggs. The hybrid males are intermediate in size and have only a hint of the the red lines typical of cecropia.

I have reared hybrids of male columbia and female cecropia. This occurs when the female cecropia placed in outdoor breeding cages fail to pair before midnight, stop calling, resume calling near dawn, and thereby attract wild male columbia, which also respond to calling female columbia which only call near dawn.

Resulting hybrid offspring are vigorous, and larvae reach sizes intermediate between cecropia and columbia. The hybrid cocoons are distinct from both cecropia and columbia. I have never had a hybrid female cecropia x columbia emerge that carried developed eggs. The hybrid females will call, however, and attract wild columbia at dawn. The male hybrids, natural and bred, have proved sexually viable with pure cecropia, although the few times I have tried rearing the progeny of such a cross, the results have been mixed.

I offer the lengthy digression above to offer what I feel may be one of the causes of the extreme variability encountered amongst various populations of A. larissa, which is known to have multiple broods throughout its distribution. I suspect, with the great number of other Antheraea species which fly at the same time and in same place as larissa, that much natural hybridization occurs, and that hybrid males may in fact be able to transmit a genetic mix through pairings with possibly several other Antheraea species.

I would hope that someday, someone will take calling females into the regions in question, place the females in inaccessible cages, and document the times at which males respond to the calling females. If males of various species respond, then I have no doubt there is substantial gene mixing. It would also be great if some hybrid pairings were obtained and stocks were reared through to adulthood.

I do not know if dna analysis is sufficient to sort out hybridization effects.

I also am very much aware that the Antheraea polyphemus populations across the United States and Canada have some populations that are remarkably consistent in size differences based on locale. When moths from the two different (size difference) locales are paired, offspring are vigorous in all stages, crossed males and females are sexualy viable and females carry fully developed eggs that show no ill effects for future generations. There is also considerable variation within locale populations with regard to colouration of both adults and larva.

Antheraea larissa ridlyi and Antheraea steinkeorum/broschi/ulrichbroschi males,
Frasers Hill, Pahang, Malaysia, courtesy of C. W. Gan.

In further commentary Nassig offers the following: "Recent research (e.g., U. & L.H. Paukstadt 1999, U. Paukstadt et al. 2000a, 2000b) delivered support that the fauna of the Saturniidae and Brahmaeidae of Java and Bali appears to be much more distinct from the Neomalayan fauna than expected by earlier authors (e.g., Nässig et al. 1996). However, the differences between Javanese and Neomalayan Antheraea larissa were demonstrated only very weakly by U. Paukstadt et al. (2000c).

"As there was at least in the most recent glaciations no long time difference between the split-off from Sundaland of Java and Bali on one side and Borneo and Sumatra on the other side (the time span for the world-wide post-glacial increase of the sea-level was probably only a few centuries or even decades!), the difference in faunal composition between Java/Bali and Neomalaya must be explained in a different way. One important difference is the climate; Java and Bali show a distinguished seasonal climate, while Neomalaya is more of a perhumid tropical climate without distinctive seasons. Therefore, at least present-day evolutionary pressure on Java/Bali is different from that on Neomalaya. The genetic exchange for less mobile bombycoid species (such as Saturniidae, Brahmaeidae etc.) would be interrupted by the sea level rising for only some thousand years now (mobile species probably still do have genetic interchange within Sundaland!); all these present-day islands became separated by sea only about 8000–10,000 years ago. This time span is probably too short for the evolution of species-specific differences in Saturniidae. Thus, there must have been isolation mechanisms established much earlier than the end of the last glaciation preventing gene-flow between Javanese/Balinese species and Neomalayan species, e.g., possibly by large rivers and swamps between Neomalaya and Java/Bali, surely in combination with the differences in climate.

"The model of the “peripherical isolates” (stressed, e.g., by Nässig & Treadaway 1997, 1998 or U. & L.H. Paukstadt 1999) should, therefore, better be seen against the background of longer time spans than only ten thousand years (at least it was definitively seen in this way by myself in 1997/1998). — It should be assessed whether morphological differences between present-day insular populations of closely related “subspecies” or “species” might be explained by climate-dependant modification alone or by genetically fixed differences, and further, if there are any relevant genome differences, they should be studied into more detail (best using alloenzymes or DNA analyses) to find a time-scale for the separation of the different populations and assess the extend of the genetical separation.

"The climatical differences are gradual and clinal; the seasonality is already developed in southern Sumatra (especially in the provinces of Bengkulu and Lampung, see map) and becomes much more expressed across Java and Bali from the West to the East. Differences which are considered as being of species-specific or subspecific quality should therefore be studied into more detail along this distance from S. Sumatra to Bali on basis of larger material from several localities each."

Antheraea larissa ridlyi male

Antheraea larissa ridlyi male, Pahang, Malaysia, courtesy of Kelly Price, id by Bill Oehlke.

FLIGHT TIMES AND PREFERRED FOOD PLANTS:

Teemu Klemetti offers the following regarding flight on peninsular Malaysia: "Antheraeas flew for the whole period 8th of March-26th of May. They may have peaks March-May and October-December - males 1:00-5:00 am, females 8:00pm (rosieri) or midnight (youngi, ulrichbroschi)."

I recently saw an image of A. l. ridlyi taken December 29 at Taman Negara Park headquarters (Kuala Tahan) in north central Pahang, Malaysia.

Antheraea larissa ridlyi larva probably feed on Shorea glauca (Dipterocarpaceae).

Antheraea larissa ridlyi female, Malaysia, courtesy of Wayne Hsu.
Species id by Stefan Naumann.

Antheraea larissa ridlyi female, Sarawalk, Borneo.

ECLOSION, SCENTING AND MATING:

Females attract the night flying males with an airbourne pheromone.

Antheraea larissa ridlyi female, Cameron Highlands, Pahang, Malaysia,
170mm, November 2003, courtesy of Kelly Price

Antheraea larissa ridlyi female, Ranong, Malay Peninsula, Thailand, 100m.

Stefan Naumann indicates the subspecies classification is probably not warranted.

Males have falcate wings. The females have much larger hyaline areas, and wings are not quite so falcate.

Antheraea larissa ridlyi male

Antheraea larissa ridlyi ?? male, Cambodia, 166mm, courtesy of Bill Garthe.

The image of the Antheraea larissa posted above courtesy of Bill Garthe was listed (perhaps innacurately by seller) as being from Cambodia. This would represent an expansion of the larissa complex into that country. The specimen might be nominate larissa, larissa ridlyi, or an unnamed subspecies.

EGGS, LARVAE, COCOONS AND PUPAE:

It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive. Experimenting with closely related foodplants is worthwhile.

Shorea glauca......

Sal

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The pronunciation of scientific names is troublesome for many. The "suggestion" at the top of the page is merely a suggestion. It is based on commonly accepted English pronunciation of Greek names and/or some fairly well accepted "rules" for latinized scientific names.

The suggested pronunciations, on this page and on other pages, are primarily put forward to assist those who hear with internal ears as they read.

There are many collectors from different countries whose intonations and accents would be different.

"Antheraea" is derived from either the Latin "anthra" referring to pollen held in the anther (top part of stamen = male part of flower) or from the Greek feminine of "anthros" meaning flowery. There may be a link to the large and feathery antennae which distinguish many of the males of this genus.

The species name, larissa, is from Greek mythology where Larissa is the mother by Poseidon (Neptune) of Pelasgus.

The subspecies name, ridlyi is honourific for Ridly.

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