This late in the breeding season, the usually highly variable Anise Swallowtail caterpillars (Papilio zelicaon) under different conditions are invariably darker forms. There is quite a bit of observational evidence that many caterpillars take on specific color forms based on temperature or photoperiod either as a way to enhance camouflage during a specific time of year or to help with thermoregulation since darker colors retain greater amounts of heat than lighter ones. We have noticed this in a number of species we have reared, particularily the Anise Swallowtail (Papilio zelicaon). We have also observed 100% of our Achemon Sphinx (Eumorpha achemon) and Imperial Moth (Eacles imperialis) caterpillars taking on brown forms when reared completely indoors (where there is no sunlight exposure). While we have not compared this result to outdoor rearing (we have not had the chance yet), this is somewhat unlikely unless some other factor besides random phenotypic distribution is at work. We are somewhat doubtful that host plant has a significant impact on this as some sources claim. The Anise Swallowtail is one species that we have had the chance to observe quite closely though, and in a earlier post this year we described how we noticed their tendency to lean toward lighter morphs when exposed to greater amount of sunlight or darker morphs when reared indoors. With this particular species, both thermoregulation and camouflage seem to be reasons for this phenomenon. Sunlight exposure increases body temperatures and therefore it would be beneficial to have less black coloration on the body so as to retain less heat. And towards the end of the season when there is less sunlight, their umbel (Apiaceae) host plants (particularly fennel [Foeniculum vulgare], which also happens to be their preferred host plant in our locality) are usually mature and therefore have much more "thinned out" leaves (less dense needles) so it would make sense to have thinner green bands on the caterpillar. Most of these observations, as stated before, were comparing outdoor reared summertime individuals with summertime indoor reared individuals and less frequently with individuals actually reared in the fall time where temperatures are naturally lower and there is less sunlight. But now we do; now that it is November, our three dozen fifth instar Anise caterpillars that we reared from eggs layed by a wild caught female in October are invariably dark forms. They have been reared outdoors stating from the third instar which usually results in extraordinary light morphs in the summer. This is not a coincidence. - Brian
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Timeline 2012–2017
Albany, California This timeline is a series of daily posts recording our observations on and experiences with various insects in Albany California and surrounding areas, from 2012-2017. Since we did not publish this site until 2016, posts before that were constructed retroactively. Starting in August 2017, we moved to Ithaca, New York; posts from there on can be viewed at Timeline 2017-present: Ithaca, New York. Archives (1,011)
August 2017 (49) July 2017 (121) June 2017 (79) May 2017 (77) April 2017 (91) March 2017 (35) February 2017 (12) January 2017 (10) December 2016 (12) November 2016 (26) October 2016 (49) September 2016 (84) August 2016 (94) July 2016 (99) June 2016 (53) May 2016 (21) April 2016 (4) January 2016 (1) August 2015 (3) July 2015 (3) June 2015 (2) June 2014 (3) May 2014 (1) April 2014 (3) March 2014 (3) December 2013 (2) November 2013 (2) October 2013 (5) September 2013 (11) August 2013 (15) July 2013 (9) June 2013 (5) May 2013 (4) April 2013 (3) March 2013 (2) February 2013 (3) January 2013 (2) December 2012 (2) November 2012 (1) October 2012 (2) September 2012 (2) August 2012 (5) July 2012 (1) June 2012 (1) Authors
![]() ![]() Full Species List (Alphabetical by scientific name) Note: - Not every species we encounter is necessarily presented on this site, rather a selection of those that were of particular interest to us and that we felt were worth documenting. - We can't guarantee that all species have been identified accurately, particularly taxa we are not as familiar with. Lepidoptera Actias luna Adelpha californica Agraulis vanillae Allancastria cerisyi Antheraea mylitta Antheraea polyphemus Anthocharis sara Argema mimosae Attacus atlas Battus philenor hirsuta Bombyx mori Caligo atreus Callosamia promethea Coenonympha tullia california Citheronia regalis Cricula trifenestrata Danaus plexippus Eacles imperialis Erynnis tristis Estigmene acrea Eumorpha achemon Eupackardia calleta Furcula cinereoides Heliconius erato Heliconius hecale Heliconius sapho Heliconius sara Hyalophora cecropia Hyalophora columbia Hyalophora euryalus Hylephila phyleus Hyles lineata Junonia coenia Langia zenzeroides formosana Lophocampa maculata Manduca sexta Morpho peleides Nymphalis antiopa Orgyia vetusta Orthosia hibisci quenquefasciata Pachysphinx modesta Papilio cresphontes Papilio eurymedon Papilio glaucus Papilio machaon oregonius Papilio multicaudata Papilio polyxenes asterius Papilio rumiko Papilio rutulus Papilio zelicaon Phyciodes mylitta Phyciodes pulchella Pieris rapae Plejebus acmon Poanes melane Polites sabuleti Polygonia satyrus Pyrgus communis Rothschildia jacobaeae Samia cynthia advena Samia ricini Smerinthus cerisyi Smerinthus ophthalmica Strymon melinus Trichoplusia ni Uresephita reversalis Vanessa annabella Vanessa atalanta Vanessa cardui Unidentified Lepidoptera Hybrids Papilio glaucus × Papilio rutulus Papilio polyxenes asterius × Papilio zelicaon Orthoptera Melanoplus devastator Phaneroptera nana Pristoceuthophilus pacificus Scudderia mexicana Trimerotropis pallidipennis Phasmatodea Carausius morosus Phyllium giganteum Mantodea Mantis religiosa Phyllocrania paradoxa Hymenoptera Apis mellifera Bombus vosnesenskii Brachymeria ovata Linepithema humile Pediobius sp. Polistes dominula Xylocopa varipuncta Unidentified Diptera Lucilia sericata Unidentified Hemiptera Brochymena sp. Leptoglossus sp. Nezara viridula Odonata Argia vivida Libellula croceipennis Coleoptera Coccinella septempunctata Cycloneda polita Diabrotica undecimpunctata Hippodamia convergens Araneae (Class: Arachnida) Araneus diadematus Phidippus johnsoni |