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Posts tagged “Hymenoptera

Mossy Rose Gall Wasp Larvae Cease Feeding

10-31-14 mossy rose gall IMG_0404In the spring, the 4mm-long cynipid gall wasp, Diplolepis rosae, lays up to 60 eggs (through parthenogenesis) inside the leaf bud of a rose bush. A week later, the eggs hatch and the larvae begin feeding on the leaf bud. This stimulates the abnormal growth of plant tissue, and a Mossy Rose Gall, covered with a dense mass of sticky branched filaments, is formed. The gall provides the larvae with food and shelter through the summer. In late October, when the Mossy Rose Gall is at its most colorful, the larvae stop eating and pass into the prepupal stage, in which they overwinter inside the gall. In February or March, the prepupae undergo a final molt and become pupae. If the pupae aren’t extracted and eaten by a bird during the winter or parasitized by another insect, adult wasps exit the gall in the spring and begin the cycle all over again.

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Sawfly Cocoon

Sawflies are often mistaken for wasps, but there are subtle differences in appearance, including the thick “waist” of a sawfly compared to the threadlike waist of a wasp.  Their common name comes from the females’ sawlike ovipositor which they use to cut into plants and lay their eggs.  Certain species of sawflies overwinter as pupae inside cocoons that they attach lengthwise to twigs.  These cocoons are fairly small (the pictured cocoon is just over ¼” long).  Sawfly cocoons persist even after the adults emerge in the spring, as they are made of very tough material.   Look for capped cocoons during late fall and winter, and empty cocoons, sometimes with the cap still attached, the rest of the year.


Ant Mandibles

Ants go through complete metamorphosis, passing through four stages (egg, larva, pupa, adult). Like honeybees, there are queens, female workers and male drones in an ant colony. The female worker ants have a series of “jobs” that they perform in a certain order. A young worker spends the first few days of its life caring for the queen and young. After that she maintains the nest and eventually forages for food. Like most insects, ants lack grasping forelegs and compensate for this by using their mandibles as “hands.” When the nest is disturbed, workers rush to rescue the eggs, larvae (depicted in photograph) and pupae by clasping them in their mandibles and transporting them to safety. They also use their mandibles to carry food, construct nests, and for defense.


Inside Look at Organ Pipe Mud Dauber Wasp Cells

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Each “pipe” of the Organ Pipe Mud Dauber nest consists of several sealed cells (four, in this photograph), each stuffed with spiders (typically orb-spinning spider species) and one wasp egg. When the egg hatches, the white wasp larva consumes the paralyzed spiders, which are still fresh because they are still alive. Eventually, upon finishing the spiders, the larva will form a pupa case, and spend the winter inside it. In the spring the adult wasp will emerge from the case and chew its way out of the mud cell. If you look closely at the open, back side of these three “pipes” you can see that the oldest pipe is on the left, and contains cells with wasp larvae, whereas you can see mud dauber eggs lying on top of the spiders in two of the cells on the far right, in the most recently built pipe.


Organ Pipe Mud Dauber Wasps

There are basically two groups of wasps: 1) social wasps, such as hornets, yellowjackets and paper wasps and 2) solitary wasps, species that live solitary lives and typically hunt prey for their larvae (the adults consume nectar). Mud daubers are a type of solitary wasp.   Organ Pipe Mud Daubers builds cell out of mud in which they put prey (usually spiders) that they have stung and paralyzed, but not killed. They then lay an egg on top of the spiders, and seal the cell. After the egg hatches, the larval wasp consumes the still-fresh spiders, pupates, emerges as an adult wasp and chews its way out of the cell. In this picture a female Organ Pipe Mud Dauber wasp has collected a ball of mud and is applying it to the most recent cell she is making. The name “organ pipe” comes from the shape of the “pipes”, which consist of several cells, placed end-to-end, with the most recent cell at the bottom. (Notice the new, wet mud is darker in color.)


Leafcutter Bee Cell Leaf Sections

At the risk of boring readers, I wanted to include one final Leafcutter Bee post, showing the two basic shapes that these bees chew out of leaves in order to make their incubator/nursery cells.  There are oblong pieces, roughly an inch long, as well as perfectly round, ¼-inch diameter pieces.  Each cell consists of several layers of oblong pieces rolled lengthwise which are sealed at one end with a round piece of leaf.  The round end pieces appear to be glued into place (perhaps with the pollen/nectar mixture?) at one end of the cell, leaving the opposite end open.  The cells are arranged end-to-end, with the open end of the cell placed against the sealed end of the next cell.  Together they form a nest that is somewhat cigar-shaped and is typically located a few inches down in the soil, or in a cavity.


Leafcutter Bee Cell

Congratulations to those who recognized yesterday’s Mystery Photo!  The tiny green cells are made from the leaves of almost any deciduous trees, and are cut and folded by leafcutter bees (Megachile genus). These solitary bees are about the size of a honeybee, but are much darker, almost black. They construct cigar-like nests (often in soil, holes in wood made by other insects, or plant stems) that contain several cells. After gathering and storing a ball, or loaf, of pollen inside the cell, the bee lays an egg and seals the cell shut. When the egg hatches, the larval bee feeds on the pollen and eventually spins a cocoon and pupates within it. An adult bee emerges from the cocoon and usually overwinters inside the cell. In the spring the bee chews its way out of the cell. Leafcutter bees pollinate wildflowers, fruits and vegetables and are also used as pollinators by commercial growers of blueberries, onions, carrots and alfalfa. (Photo submitted by Jan Gendreau.)