Bug of the Week – Three Micromoths

Greetings, BugFans,

A funny thing happened on the way to this BOTW.  The BugLady spent the morning on-line, trying to discover the identities of a few moths.  Suddenly, a screen popped up (and a voice came from her speakers) saying that this was a Microsoft Alert!!!  That her Internet was Blocked (it sure was – frozen solid, had to turn the computer off, and the screen came back when she restarted), that her Credit Card Info was At Risk, and Also her Photos (Yikes!!!), etc., and please call an 877 number immediately.  Yeah, right.  She always tries to practice safe surfing, but her tech guru, BugFan Becca, told her that internet evildoers sometimes plant their little bombs on obscure sites because the security there may be lax compared to bigger sites.  No surprise, if you call them back, they’ll be happy to take your credit card number in exchange for fixing the problem.  The BugLady was also assured that no bad stuff will travel with this post.

So – microlepidoptera are, as you’d expect, a big group of small moths.  It’s not exactly a scientific classification; there’s no single structure or life style that definitively says micro or macro.  To some extent, it’s a grouping that’s determined by the size of the moth; there are some families that include both macro and micro species, and the families of the micros tend to be more primitive than those of the macros.  As Wikipedia says, “Plans to stabilize the term have usually proven inadequate.” The group is very diverse and includes a bunch of day-flying species, and the biographies of many have not been written.  Remember – of the 18,000 or so species of Lepidopterans in North America, more than 11,000 are moths. Here are three (and a half) of them.

syncopacma nigrella13 10

SYNCOPACMA NIGRELLA (no common name) is on the BugLady’s “porch bug” list; it showed up on a fine evening in late August.  It belongs to the Twirler moth family Gelechiidae, a large family with about 4,500 species globally (650 in North America). The family contains species that are agricultural pests and species that are biological controls of agricultural pests.

Syncopacma nigrella one of about five species in its genus in North America; this species is mostly found in the eastern US, but it also occurs in California, Wyoming, and Washington.  It’s about a half-inch long, and the slim, fringed wings are typical of the family.

Gelechiid larvae often feed under cover, on the insides of their host plants – Syncopacma nigrella prefers lupines (of which the BugLady has none).

We have met Crambid moths/Grass moths/Crambid snout moths (family Crambidae) before, in the form of the orange mint moth, the white-spotted sable moth, and the eastern grass veneer moth.  Crambids have wingspreads of ½” to 1 ¼” and have tympanal organs (ears) on their abdomens and hairy mouthparts that extend forward (and that put the “snout” in “snout moth”) (the hairs are sensory and give the moth information about its surroundings).  According to bugguide.net, the larvae are stem borers, root feeders, leaf tiers, and leaf miners, and the larvae of one group is only found in the nests of arboreal ants!  Adults of some species seek nectar on flowers and probably do a little pollinating.

The BugLady gets a kick out of the subtle patterns and silvery accents that are sported by some grass veneers, and by the way they sit, wings rolled up instead of folded over their backs.  The grass veneers are said to be twig mimics.

agriphila grass vnr15 1

The VAGABOND CRAMBUS (Agriphila vulgivagellus) is also called the Vagabond sod webworm, which gives us a clue to what the larvae do for a living.  The species can be seen in late summer and early fall around grasslands and gardens, from the Atlantic coast to the Great Plains and north into Canada.

Adults are found perched in the grass by day, and are crepuscular (dawn/dusk) and nocturnal flyers. They fly over the grass-tops in September, sometimes in large numbers, drinking dew from the blades, and females lay eggs (60 per day for two weeks) by dropping them into the grass as they fly.  The larvae feed on a variety of grasses and grains.  They overwinter as immature larvae that awaken in spring and feed on grasses from a webbed tube they construct on the ground.  The vagabond sod webworm has a single generation per year and is not considered as serious a pest as other species of sod webworms because the grass blades they eat in fall and in spring are growing fast.

julie's dicymolomia16 8

JULIA’S DICYMOLOMIA (Dicymolomia julianalis) led the BugLady on a merry chase through moth books and websites.  She found this lovely creature (and another species to be named later) on composites in early summer.  It is also in the Crambid family and is also found over the eastern side of North America.  The moth could perch on the BugLady’s thumbnail with plenty of room to spare.

The larval menu is diverse and includes cattails, the primary host, but also Opuntia cacti, a few composites, and the egg clusters of evergreen bagworms.  Eggs are inserted into cattail heads in mid-summer, and the larvae feed on fresh and then dried flower parts and on the seeds, digging deeper into the cattail head as they get older (a little lump on an otherwise-smooth cattail shows where they are feeding). The larvae spin silk through their chambers to hold the cattail head together and keep the seeds from scattering.  Half-grown larvae overwinter in the cattail head, and they also pupate there in early summer.

And the half-moth?

The BugLady chased these beautiful rust and silver moths around the Riveredge prairie, and when she put her pictures up on the screen, she (eventually) noticed some variation in pattern that hadn’t registered out in the field (and this is why her field identification skills are going south – she can sit and stare, with a book in her hand, at insects on a screen, and they don’t fly away (except, see paragraph one)).  She realized that one species (which turned out to be Julia’s Dicymolomia) had silver “suspenders” across the top of its wings, and the other had a horizontal silver band across the wings, about a quarter of the way south of the head.  Same patch of prairie, same time of day, same time of year, same composites.

x chalcoela15 4

Still looking – being careful of obscure moth sites – if it’s not a Dicymolomia, it might be a Chalcoela.  If anyone else would like to play, try http://bugguide.net/node/view/39603/bgpage and http://bugguide.net/node/view/29597/bgpage.  And maybe an adult beverage.

Kate Redmond, The BugLady

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