This particular lilac bush is more like a tree with its multiple 6+ inch diameter gnarly trunks and 20+ foot height. We estimate it is over 70 years old based on the age of the homestead and the knowledge that the lilac was already well-established when the old house was torn down to build the current house. The branch in question was about 14 feet high, but a regular ladder was out of the question because there would be nothing safe to lean it against. I couldn't back my pickup close enough without scratching it...what to do? Dad to the rescue! He fired up his dump truck and had it backed into the lilac in no time, let down the metal panels on the back so we could climb up in it, then set up a six foot step ladder in the bed, which was about four feet off the ground. I was then able to climb almost to the top of the ladder and pull the branch towards me. After a couple minutes of searching I located the leaf and found the egg!
|Looking for the Western Tiger Swallowtail (Papilio rutulus) egg on our giant lilac bush. Photo courtesy of Mom, truck and ladder courtesy of Dad :)|
|Our unconventional setup|
|Success! Western Tiger Swallowtail (Papilio rutulus) egg on lilac|
With egg in hand, I then started thinking that I didn't recall ever reading anything about Western Tigers using lilac as a larval host. A few book and internet searches later, and the only reference to lilac I could find was Art Shapiro's website citing lilac as a host in California. Willow (Salix), poplar/cottonwood/aspen (Populus), wild cherry (Prunus) and ash (Fraxinus) are listed as the hosts everywhere, with sycamore (Platanus), privet (Ligustrum) and sweet gum (Liquidambar) also listed by Art Shapiro. Interestingly, lilac (Syringa) is in the olive family: Oleaceae, which ash and privet both belong to. After talking to Washington lepidopterists, it seems my find is the first record of Western Tigers using lilac in Washington, possibly even anywhere outside of California (if you have recorded them on lilac anywhere, shoot me an email). It is likely that it has just been overlooked all this time, or perhaps they prefer old (i.e. tall) heirloom varieties over more recent varieties that might be less attractive to the butterfly. In any case, if you have lilac bushes, closely watch your tiger swallowtails to see if you notice any strange behaviors around them instead of simply nectaring on the flowers! Now is the time of year to look for tiger swallowtail larvae on all of the hosts listed above - watch for a caterpillar resting in the center of the top of a leaf. Early instars look like bird poop but become a camouflaged green with two large "snake eyes" as they mature. If you find any let me know!
|My adorable little cutie-pie, barely a millimeter across with little teddy bear ears|
|Western Tiger Swallowtail (Papilio rutulus) larva at about 5mm long soon after hatching.|