{"id":13692,"date":"2023-04-19T12:44:40","date_gmt":"2023-04-19T17:44:40","guid":{"rendered":"https:\/\/uwm.edu\/field-station\/?p=13692"},"modified":"2023-04-19T12:44:43","modified_gmt":"2023-04-19T17:44:43","slug":"birch-catkin-bug","status":"publish","type":"post","link":"https:\/\/uwm.edu\/field-station\/bug-of-the-week\/birch-catkin-bug\/","title":{"rendered":"Birch Catkin Bug"},"content":{"rendered":"\n

Note: All links leave to external sites.<\/small><\/p>\n\n\n\n

Howdy BugFans,<\/p>\n\n\n\n

When the BugLady started this little project in the summer of \u201ctwenty \u2018aught seven,\u201d she had two criteria for candidates for the bug of the week \u2013 that she had taken a decent picture of the bug, and that she was able to find an interesting story about it. Today\u2019s episode sets the bar pretty low for picture quality.<\/p>\n\n\n\n

This adventure started with a (very) bad photograph. Last week, the BugLady headed to a little bog that she frequents so she could test drive her new macro lens. She photographed the spiffy male catkins of an alder, and then she aimed the camera overhead at a cluster of last year\u2019s female cones, just to see what the lens would pick up. A \u201cthrowaway shot.\u201d When she put the picture up on the screen that evening she realized that the camera had seen a bunch of small bugs that she had not, and although she massaged the image, it was still pretty sad. So she went back the next day – with much the same result. That\u2019s how it goes, sometimes, but here are some splendid pictures of the bug<\/a>.<\/p>\n\n\n\n

The first thing she noticed on Trip #2 is that although she checked the cones on alders all along the boardwalk, she only saw the bugs on alders that grew fairly close to the shoreline of a small, adjoining lake. The second thing she noticed is that these bugs are slippery little devils – when she gently hooked the branch of a tall alder to bring the cones down to camera level, the bugs had vanished by the time the cones got close. The third thing she noticed is that this was a bug that she\u2019d never seen before (a \u201cTrue bug\u201d in the Order Hemiptera, and the suborder Heteroptera, because of the \u201cX\u201d arrangement of the folded wings on the back).<\/p>\n\n\n\n

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Brief, slightly technical digression (but it\u2019s spring, but our brains are yawning and stretching and greening up, and we\u2019re up for this): Once upon a time, there was an insect order called Homoptera, which included cicadas, leafhoppers, spit bugs, scale insects, aphids, and the like. A separate order, Hemiptera, was called the \u201cTrue Bugs,\u201d and it included stink bugs, leaf-footed bugs, assassin bugs, seed bugs, etc. \u2013 the guys with the X\u2019s on their backs. The two Orders were merged, under the umbrella of \u201cHemiptera,\u201d and the true bugs are now in a suborder called Heteroptera (which means \u201cdifferent wings<\/em>,\u201d because their front pair of wings is leathery at the base and membranous at the tip).<\/p>\n\n\n\n

BIRCH CATKIN BUGS (Kleidocerys resedae<\/em>) are in the suborder Heteroptera and in the Seed Bug family Lygaeidae \u2013 \u201cSeed bugs\u201d because most family members (like Milkweed bugs) feed on seeds, puncturing them with piercing mouthparts. Due to the chemicals they pick up from the plants they eat, many Lygaeids don\u2019t taste so good, and some (like Milkweed bugs) are clad in bright colors to advertise that fact. Most Lygaeid species also have stink glands, and so the term \u201cstink bug\u201d may be applied pretty loosely, but the Hemipterans that are officially called Stink bugs belong to the Stink bug family Pentatomidae. Birch catkin bugs have an odor that some people call strong and unpleasant, but that blogger Larry Hodgson, the Laidback Gardener<\/em>, described as \u201cintense, with a hint of wintergreen<\/em>.\u201d<\/p>\n\n\n\n

The BugLady was surprised to learn that this little bug\u2019s range is Holarctic, a term that refers to much of the Northern Hemisphere, around the globe. It didn\u2019t come over on the boat – it\u2019s native to northern portions<\/a> of both the Old World (the Palearctic) and the New (the Nearctic), and it\u2019s never far away from its host plants in the genus Betula \u2013 the birches. The BugLady found some good information about it on nature sites in the United Kingdom.<\/p>\n\n\n\n

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If you figure that a mature alder cone is about two-thirds of an inch long, you can see that these are very small insects, indeed \u2013 maybe 3\/16\u201d long, max. They are generally rusty-colored, with clavate (clubbed) antennae, and they\u2019re \u201cdensely punctate<\/em>\u201d \u2013 covered with small pits or punctures [1<\/a>, 2<\/a>, 3<\/a>, 4<\/a><\/strong>].<\/p>\n\n\n\n

Birch catkin bugs eat birch seeds, which are found in the female catkins\/cones. Although the nymphs have a strong attachment to their birch host plants, adults do use other trees and shrubs, like the Ericaceae (heathers and blueberries) and the Rhododendrons; bugguide.net<\/a> lists \u201calder, and other deciduous trees\/shrubs<\/em>\u201d among the adult food plants. The BugLady guesses that the bugs she saw were looking around for any of last-year\u2019s seeds that may have weathered the winter within the cones, since the new alder cones won\u2019t be producing seeds for a while.<\/p>\n\n\n\n

They overwinter as adults, sheltering in old, fallen catkins and in leaf litter (though in some areas where there are several generations per year, nymphs may also overwinter). They wake in spring and mate in June, and according to several sites from the United Kingdom, \u201cwhikst<\/em> [sic] flying they emit a vocal mating calls using a strigil [a comb-like scraper] located on one of the hind wing veins<\/em>.\u201d Females lay eggs on old, female birch cones.<\/p>\n\n\n\n

THE RABBIT HOLE DU JOUR<\/em>: The BugLady was curious about the statement about Birch catkin bugs emitting mating calls in flight. Rubbing two body parts together to produce sound is called stridulation, and it isn\u2019t uncommon \u2013 think locusts and katydids – but it\u2019s not universal, either. Milkweed beetles stridulate, and Hemipterans like tree hoppers do, too, and depending on the species, adults, larvae, and even pupae may stridulate. Here\u2019s what she learned from a wonderful (and very scholarly) paper in Biological Reviews<\/em> called Sexual selection and predation drive the repeated evolution of stridulation in Heteroptera and other arthropods, by L. Davranoglou, G. Taylor, and B. Mortimer.<\/p>\n\n\n\n