Late-Autumn Insects

Last week, the coming winter teased us with snow flurries mixed in with the rain. But, during the first week of November, the temperature rebounded to the 70s. The breeze is gentle, the afternoon sun is hot and a few insects are active in some sun-warmed patches of our backyard.

On the garden’s last purple coneflower, a yellow-green, spotted beetle, similar to a ladybug at first glance, nibbles on the coneflower’s center.  It is a spotted cucumber beetle (Diabrotica undecimpunctata).  And, though it’s a garden pest, it won’t survive the Minnesota winter, so I let it stay. It looks beautiful on the deep magenta bloom.

Spotted Cucumber Beetle

Spotted cucumber beetle (Diabrotica undecimpunctata) on a purple coneflower.

Across the yard in another sunny spot, bright red insects huddle together on a common milkweed pod. They include three different developmental stages, or instars, of the same insect, the large milkweed bug, (Oncopeltus fasciatus).  They use a tubelike mouth to inject digestive enzymes into the pod and then suck out the partially digested plant material.  Because they eat milkweed, they have the same toxicity found in monarchs and other insects that dine on the plant.  When I first noticed them a few weeks ago, I thought they were red aphids until I spotted an adult on the pod.  Over time, they began to grow larger, develop black markings, and become darker red.  Like the spotted cucumber beetle mentioned above, the large milkweed bug is migratory and those still here won’t survive our northern winter.

Early instars of Large Milkweed Bug

Early developmental instars of large milkweed bug (Oncopeltus fasciatus).

Large milkweed bug in developmental stages.

Large milkweed bug in several developmental stages on a common milkweed pod.

The orange shells of Asian lady beetles (Harmonia Axyridis) glow where they’ve settled on the sun-warmed brick of our house and on a few hardy garden plants.  Unlike the insects mentioned above, these beetles survive the Minnesota winter.  They were introduced into the southern United States in the mid-1900s to help control agricultural pests and first appeared in Minnesota in the 1990s, according to University of Minnesota records.  To some people they’re pests because the beetles often find a way inside in the autumn. But, they also eat aphids found on trees, in gardens and on agricultural crops.  The easiest way to distinguish Asian lady beetles from native species is by an “M” or “W” mark (depending on the viewing angle) on the thorax between the head and abdomen.  (More about Asian and native ladybird beetles in another post.)

Asian lady beetle on goldenrod.

Asian lady beetle (Harmonia Axyridis) on goldenrod.

Asian lady beetle on 'Henry Kelsey' rose.

Asian lady beetle on ‘Henry Kelsey’ rose.

Variety in an Urban Milkweed Patch

Most of us learned about the special relationship between monarch butterflies and milkweed plants when we were young children — and just about anytime I look in our garden, monarchs sail among the milkweed.  Females lay eggs on the underside of leaves and monarchs of both genders sip the plant’s sweet nectar.  But milkweed isn’t just for monarchs!  It also provides a place for many other creatures:  A few that are immune to its toxicity eat it; others drink its nectar, depend on it for reproduction, watch for a meal, or simply rest. Here’s a sampling of critters living in our backyard milkweed in early August.  What’s in your milkweed patch??

The adult red milkweed beetle (Tertaopes tetrophthalmus) eats milkweed leaves, buds and flowers.

The adult red milkweed beetle (Tetraopes tetrophthalmus) eats milkweed leaves, buds and flowers. Its larvae eat the plant’s roots.

The Large Milkweed Bug (Oncopeltus fasciatus) eats the seed pods, stems and leaves of milkweed.

The Large Milkweed Bug (Oncopeltus fasciatus) eats the seed pods, stems and leaves of milkweed.

A hover fly or flower fly (Syrphidae).

A hover fly or flower fly (Syrphidae).

 

An eastern yellowjacket (Vespula maculifrons).

An eastern yellowjacket (Vespula maculifrons) hunts for small insect pests to eat.

A honey bee (Apis millifera).

Honey bees (Apis millifera) favor the sweet milkweed nectar.

Bumble bees (Bombus) of several different species are attracted to milkweed blossoms.

Bumble bees (Bombus) of several different species are attracted to milkweed blossoms.

Red admiral butterflies (Vanessa atalanta) are attracted to the milkweed's nectar.

A red admiral butterfly (Vanessa atalanta) sips milkweed nectar.

I never tire of seeing monarchs (Danaus plexipus) nectar on milkweed blossoms.

I never tire of seeing monarchs (Danaus plexippus) nectar on milkweed blossoms.

Insects aren't the only critters to favor milkweed nectar. Ruby-throated hummingbirds (Archilochus colubris) frequently drink it, too. Insects aren't the only critters to favor milkweed nectar. Ruby-throated hummingbirds (Archilochus colubris) frequently drink it, too.

Insects aren’t the only critters to favor milkweed nectar. Ruby-throated hummingbirds (Archilochus colubris) frequently drink it, too.