|MadSci Network: Zoology|
Hi Maureen, Identifying insect eggs isn't easy at the best of times, and unfortunately without photographs it becomes much harder. The best I can do in this forum is to make an educated guess that may help narrow down the possibilities. Ideally, you should try to contact an entomologist living in Massachusetts who would be familiar with the common insects in your area and may be able to recognize either the eggs or the newly hatched insects. The University of Massachusetts at Amherst has an entomology department and one of the professors may be able to assist There are numerous insects that lay yellow green oval shaped eggs, however the fact they were found on an introduced species of plant in a cluster (as opposed to in a random clump, on stalks, or inserted into the stem) suggests that these eggs likely belong to either a butterfly or moth, a leaf beetle, or a stink bug. Fortunately, Japanese Knotweed is an introduced plant with few (if any) natural enemies in the United States. Its very unlikely that whatever insect the eggs belongs to actually eats Japanese Knotweed and this means that the eggs probably aren't from a leaf beetle, butterfly or moth. These insects produce larva that cannot disperse far from the site of hatching, so they tend to lay their eggs on the same plant the larva will feed on during the early part of their life. (There are a few exceptions, including species of caterpillar that disperse after hatching by floating on strands of silk - "balooning" - and some butterflies that will lay their eggs on unsuitable host of no suitable plant can be found.) In contrast, newly hatched stink bugs are very mobile and many species are predators. This means that the parent will lay their eggs on any conveniant plant, since the newly hatched bugs are fully capable of migrating to find food. Probably the best way to identify the eggs is to simply see what hatches out. Newly hatched caterpillars will always have a set of grooves on their head that resembles an upside down V. Newly hatched beetle larva can look similar to caterpillars, but they will never have the V shaped grooves. If the eggs belong to a stink bug or other true bug, what will emerge will look like a miniature wingless adult. It is sometimes possible to keep the insect alive until it has gone through several molts by feeding it on its host plant if itís a herbivore. Older insects are easier to identify to genus or species than younger insects, and adults are much easier to identify than immature insects. If the insect is a carnivore, however, it will be difficult to rear in captivity, and probably the best thing for it would be to release it near where you originally found the eggs. I hope I was able to help, -Tom-
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