2018 March 3

   Jeremy Tatum writes: Every year we are challenged with a photograph of a geometrid moth for which we have to decide whether it is the American Tissue Moth Triphosa haesitata or the Barberry Geometer Coryphista meadii.  Rosemary Jorna photographed the moth below in her garage in the Kemp Lake area on March 1.  After close study, Libby Avis and I agree that Rosemary’s moth is Triphosa haesitata.

  It might be wondered – if two species look so similar that they can’t easily be told apart, are they really different species?  I have a theory that, if they are really different species, then the caterpillars will be different – and in the case of haesitata/meadii the caterpillars are indeed totally different and they are quite obviously separate species.  What about Hesperia comma/colorado (the Common and Western Branded Skippers)?   I’d really like to find the caterpillars.  Until then, I’m not sure whether they both deserve the accolade of full speciesdom.

Triphosa haesitata (Lep.: Geometridae)   Rosemary Jorna

Triphosa haesitata (Lep.: Geometridae)   Rosemary Jorna

     Jeremy continues:  I saw my first Phigalia plumogeraria of the year today, on the light at the entrance to the Swan Lake Nature House.

   New Moth Book!    I received a surprise package in the mail today – a copy of a new moth book, Peterson Field Guide to Moths of Southeastern North America, by Seabrooke Leckie and David Beadle, 652 pp. Published by Houghton Mifflin Harcourt, 2018.  Apparently I get a very generous free copy, because one of the 2500 photographs in it is mine, though I haven’t found it yet!  I am not planning to go to the southeast in the foreseeable future, and I don’t suppose many of the moths down there are planning to visit Vancouver Island, but it’s a very nice book to have all the same.

2018 March 2

   Objet trouvé on a willow twig at Rithet’s Bog today – a cocoon of a Polyphemus Moth.

Polyphemus Moth Antheraea polyphemus (Lep.: Saturniidae)

Jeremy Tatum

2018 February 27

   Our contributors are making sure that Invert Alert remains in business during the winter.  Today, thanks to Jochen Moehr who sends us a couple of interesting pictures of a tick taken from his dog in Metchosin.  And thanks to Janet Sperling of the University of Alberta, who writes:  “The tick from Vancouver Island is an Ixodes but I’d need to see the specimen to know which species. The shape of the scutum suggests I. pacificus.  At this time of year, the most common species from Vancouver Island would be Ixodes pacificus but I’d need to see the mouthparts to be sure.”

Jeremy Tatum remarks:   To my untutored eye this didn’t look much like the Ixodes pacificus shown by Thomas Barbin on June 22, so I asked Dr Sperling about the two ticks.  She replied:  Both ticks appear to be Ixodes pacificus. The black scutum with red ‘abdomen’ = ‘idiosoma’ is the unfed form of the tick. When the tick feeds, it will feed over several days. There are many hormonal changes so the idiosoma can stretch as the tick feeds. The colour of the cuticle changes. It makes sense that the black and red photo was found crawling around (looking for a meal) while the other tick had been feeding on a dog.  Another interesting thing about hard ticks is that they don’t excrete the fluid portion of the blood out the back end. They re-inject the fluid part of the blood into the host which is why they’re so effective at transmitting diseases.

Tick (upperside) Ixodes (probably pacificus) (Acari: Ixodidae) Jochen Moehr

Tick (underside) Ixodes (probably pacificus) (Acari: Ixodidae) Jochen Moehr

2018 February 26

   Ian Cruickshank sends a photograph of a nest of young Silver-spotted Tiger Moth caterpillars overwintering on a Douglas Fir at Rocky Point.  Some of these caterpillars may look a little out of sorts, but they are not.  When the weather warms up a little, as I am told it will do in a few days, they will have a skin-change (ecdysis) and they will look very healthy in their new attire.

Silver-spotted Tiger Moth Lophocampa argentata (Lep.: Erebidae – Arctiinae)

Ian Cruickshank

2018 February 24

   Best to stay indoors in this weather.  We can still see a few commensal invertebrates.  Here’s a Common Firebrat  from my apartment building.  If you compare this one with the Grey Firebrat shown on January 26, you can easily see that they are separate species, not just minor colour variations of one species.  The Grey Firebrat has a longer, more slender abdomen and it is a more streamlined creature than the Common Firebrat.  The abdomen of the Common Firebrat is relatively quite short.

Common Firebrat Thermobia domestica (Thysanura:  Lepismatidae)  Jeremy Tatum