Subject: Polyphemus moth
Geographic location of the bug: Seattle
Time: 11:14 PM EDT
Your letter to the bugma: Hi – I Found a polyphemus caterpillar in the mail box(!?) and transferred it to an observation tank placed in a classroom. I provided pin oak leaves and the caterpillar has spun a cocoon. One website said the cocoon needs to over-winter in a cool place and will emerge in June. Another website said it will emerge in a couple of weeks. I would love for this marvelous creature to be able to survive and emerge – any suggestions?
How you want your letter signed: Candace Robbins
This is indeed a Polyphemus Moth Caterpillar. Overwintering in a cool place is excellent advice, but the June emergence is probably information for a location with a cold winter. According to BugGuide: “In southern United States, adults fly April–May and July–August (2 broods); in northern part of range, adults fly from May to July (1 brood).” BugGuide lists Washington sightings from April to October, which leads us to believe you may have two generations, so emergence might happen well before June, possibly even in several weeks. We just located information that disputes that supposition, because according to Pacific Northwest Moths: “Our populations are most likely single-brooded with capture dates from mid-April until August. Second-brooded populations exist in areas with warmer climates.” You might be able to witness eclosion in April.