Catching Common Buckeyes at Tilden

Common Buckeyes (Junonia coenia) butterflies are super common; we were catching them by the handfuls at Tilden Regional Park (Berkeley, CA) today!

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Last time we caught some Common Buckeye (Junonia coenia) butterflies was a few weeks ago on 6/14 and 6/15 at the Ohlone Greenway. At that time, we were sort of just messing around and just wanted to take a few shots of them for the record's sake.

Even now we have never encountered any of their caterpillars or eggs despite the butterflies being so incredibly common along dry grassy areas such as along the Ohlone Greenway, the bottom of Albany Hill, and the hiking trails at Tilden Regional Park. In fact, we hadn't really even looked into what their host plants were until this year! Presumably, the Common Buckeyes around here utilize plantain (Plantago) since that is what is commonly found around here and it is also around the dry grassy areas that that the butterflies like to hang out. But most of the plants look quite small and unappealing (unsustainable for reasonably large caterpillars) and coupled with the fact that it is so abundant, the chances of finding any caterpillars and eggs is, indeed, pretty low.

This afternoon starting around 2 PM when we went to Tilden to pick leaves for our Pipevine Swallowtails (Battus philenor), we also decided to bring along with us our new butterfly net. Lucky for us, there were plenty of butterflies around when we went on one of the trails; unluckily, we weren't able to catch most of them. Well, except for the Common Buckeyes, that is. Everywhere along the dead grasses lining the trail today, there were Common Buckeyes that we probably saw well over ten of them within just half an hour. They were all just lying there (roosting), sunning themselves and having a good time. At any rate, they were extremely easy to catch with our net and we soon collected a total of five of them very quickly. Despite the fact that they would probably turn out to be all males since sunning is a typical male behavior in this particular species (females are rarely seen and only come out to lay eggs at the host plant), we still took our chances. 

When we got home, we immediately tried to sex them to confirm our suspicions. Common Buckeyes, like most brush-footed butterflies (Nymphalidae) look pretty much identical between sexes and have extremely small genitalia so it can be an impossible task. But eventually what we discovered was that one of the five appeared to have different looking genitalia then the rest and we assumed that this meant that we had both sexes and that this was a female. Of course, we could have been wrong and they really were all males (I don't suppose they are all females!) but we decided in the end to put all five into a ovipositing enclosure that we set up. Basically, it was a plastic jar with some plantain leaves and a piece of window screening as the lid to provide some ventilation and prevent overheating of the butterflies. We also provided a paper towel soaked in a solution of Clover honey and water as a food source. Since it was getting late, we had to use a heat lamp over the lid to light it up and provide some much-needed warmth to stimulate activity. However, the butterflies seemed to be extremely tired and stressed out for the day and would need some time to get used to the new environment anyway, so we gave up and figured that we would probably need to wait until tomorrow to see if they would lay any eggs for us. Hopefully it does works out and we can rear this species for the first time!

- Brian