Anise Swallowtails (Papilio zelicaon) are super common here, and with the mid-June heat rolling in they have certainly begun to peak for the season. In this post, we go over a recent egg hunting trip and the isolated plant technique. This Wednesday, we scheduled another one of many trips to El Cerrito's Ohlone Greenway from Brighton Ave. to Fairmount Ave to forage for Anise Swallowtail (Papilio zelicaon) eggs and caterpillars. It had actually been over two weeks since the last time we had come searching which is relatively long considering will typically go every weekend so we hoped that they would have accumulated by now. The Ohlone Greenway is an isolated walkway stretching from city to city along the BART tracks with a decent amount of native plants and trees growing wildly. However, in a lot of places of the trail (including the section we went to today) the city must have decided to cut down on the plants directly under the BART tracks so they could screw up the soil and plant other things like grass and flowers in what we suppose is an attempt to make the trail look more friendly. While this is pretty artificial and destructive of the native habitat, it is good for one thing -- wild fennel (Foeniculum vulgare). Originally introduced from Europe, the little intruder grows incredibly well here in Northern California. You see, F. vulgare is extremely opportunistic and will readily take advantage of any "disturbed areas" where the topsoil has been removed in a ridiculous case of secondary ecological succession. Needless to say, "disturbed areas" are very common in the urban setting and the Ohlone Greenway is no exception. Wild fennel grows to be much large than the stuff you find in grocery stores and once established is impossible to get rid of due to its huge taproot (it is in the carrot family after all!). Anyway, the Anise Swallowtail's number one most preferred host plant by a very generous margin is none other than the slimy F. vulgare. Not too long ago considered a relatively "rare" species, the Anise Swallowtail population is now booming due to the recent arrival and rapid spread of F. vulgare and they seemed to have all but forgotten about the hardy little native umbelifers that they normally would have utilized. In fact, so many native plants are becoming increasingly rare here that it would be very difficult to find any native host plants such as Water Parsley (Oenanthe sarmentosa) and Yampah (Perideridia spp.) around anyhow, unless you were to search up into the mountains. But, after all, P. zelicaon's ancestral species most likely utilized F. vulgare back in Europe anyway before even arriving to North America so its not a surprise that they would so readily revert back to it. Based on our own experience, the move to wild fennel in the city was a very quick one. The first time we found Anise Swallowtails eggs three years ago in 2013, they were on parsley from a local vegetable garden. From there, we consistently found the eggs in nurseries on their parsley and dill that year. At the time, wild fennel was relatively uncommon here in Albany and was not nearly as rampant as it is now. There certainly wasn't very much of this big weed on the Ohlone Greenway or in anybody's front yards. For a long time we were not even aware that the butterflies would lay their eggs on fennel since we could never find any there. Ironically, that year was the last and only year that we have ever found Anise eggs on anything other than the sly F. vulgare. Since 2013, fennel has tightened it grip in our region with incredible speed and the Anise Swallowtails have followed suite, rewarding it with the status of being it's most preferred host plant here on the coast of California. Yet, even with what look like fields of wild fennel growing everywhere under the BART tracks on the Ohlone Greenway, we failed to collect even a single egg or caterpillar from there on today's trip. Why? Simply because there's too much there in that particular area. . . . When looking for most butterfly eggs or caterpillars, following the "isolated plant technique" or "edge effect" is your golden rule of thumb to maximize efficiency. We have found that it works especially well with Anise Swallowtails. In essence, it is strategic to search on isolated host plants in noticeable open areas rather than where the plant is very dense. This technique is based on a few simple principles:
At the same time, the fennel fields growing under the BART tracks are almost always under the shade of the tracks. In order to increase the chances of finding eggs or caterpillars, the plants must be in an open, exposed area that receives direct sunlight because the sun is directly responsible for warming up the Anise butterfly's body and inducing oviposition. . . . Keeping all of these points in mind, we knew we had hit it hard when we came to the very end of this section of the trail to Fairmount Ave. and found a single medium-sized, healthy fennel plant sitting in the sun. From this single plant we reaped the majority of 92 Anise eggs and 19 caterpillars we collected today. - 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 |