Pipevine Larvae are Ripe for the Picking

5/29/2017

After not collecting pipevine swallowtail (Battus philenor hirsuta) larvae for over two weeks, we were shocked by the absurd amount of larvae that were up in the Berkeley Hills today.

We decided to skip off on last week's pipevine collecting trip since we already had hundreds to deal with, and we doubted we were going to find any eggs anyway as the egg season was just about ending. However, we decided to go again today - not to collect eggs, but to see if there were older larvae, particularly fifth instars, that we could just collect and have pupate within a week.

Well, when we arrived up in the Berkeley Hills, it turned out we were right about there being many larvae just ripe for the picking, but we were simply shocked at the massive number of them! We had already collected hundreds of eggs and larvae here and weren't expecting to find many more, but it looks like we missed at least half of them, as there were simply larvae everywhere on the vines - many of them fifths, meaning they had been here all along for several weeks. These wild larvae behave nothing like the ones in captivity, being extremely active and sensitive, crawling from plant to plant to feed and extending their osmeteria instantly when disturbed to release a orange fluid. The wild larvae are also much redder due to being in the sun, with red on the normally black elongated scoli on the thorax and the rear.

After collecting for over an hour, we had a tub full of over a hundred larvae - a good half of them fifth instars, but also many fourths and a few thirds and seconds. There were no first instars and only one old egg cluster, clearly indicating the egg season is over and only large larvae are present. Pupae probably already exist in the wild at this point as well. When we got home, we dumped all the newly collected larvae into a new tub to separate them from the old captive ones. Though the first several captive larvae we reared were very large and healthy, these days they are coming up much smaller, but the wild ones look much larger and will give our stock a fine boost. We just hope they aren't parasitized.

Authors
Alan Liang

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