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Lichtensia viburni - Larva (1st stadium)
Adding another development stadium for this species. This is the first and quite tiny stadium (~0.5mm). It is mobile and after hatching from the eggs finds itself a place to bore into the plant to feed. In the case of male individuals it will hence forth remain in that very spot for the rest of the development cycle. Females move about around their next moults to find better spots for feeding and oviposition.
It being a Hemiptera would dictate addressing these as "nymphs" but most literature seems to use the term "larva". As a matter of fact the development cycle of the likes of these is one of the reasons that some authors suggest dropping the term "nymph" altogether as it is near impossible to draw a clear line between the two. I've decided to dedicated one image to the nymph and larva advocates each :o)
The Viburnum Cushion Scale (Lichtensia viburni) is a soft scale insect (Coccidae), originally described from Viburnum but quite polyphageous and known as a pest of olive groves in the Mediterranean region.
comments (4)
- Insect Larvae, Nymphs, and Pupae
, where my description is:"This list includes all kinds of insect larvae! Insects can have complete (holometabolous) or incomplete (hemimetabolous) metamorphosis. Those with complete metamorphosis have four life stages: egg, larva, pupa, and adult (imago). Orders that contain a larval life stage include: Coleoptera (beetles), Diptera (flies), Hymenoptera (ants, bees, wasps), Lepidoptera (butterflies and moths), Mecoptera (stoneflies), Megaloptera (alderflies, dobsonflies, fishflies), Neuroptera (lacewings, antlions), Raphidioptera (snakeflies), Siphonaptera (fleas), Strepsiptera (twisted-winged parasites), and Trichoptera (caddisflies)."
BUT, there have been so many instances where I want to add nymphs to my list. But, nymphs aren't larvae. Or, are they. I feel the need to loosen up, change my list description, and include the nymphs. Don't want to be prejudiced against the cute nymphs. Posted 4 years ago
Now imagine that for a certain group of insects the main researchers and hence the leading publications have been French for a while. All biologists that have been "reading up" on that group will have grown accustomed to the French term "larve", for what in their native language (German, Dutch, English ...) should have been called a "nymph" (or language equivalent de:Nymphe, nl:nimf, en:nymph, es;ninfa etc).
I suspect this is the reason that in German and to a lesser extend also in Dutch, many many leading authors have grown accustomed to using the word larva for the youngsters of Heteroptera and Orthoptera, even when they write in their native language.
This is but one part of the "confusion". The other part is that for various groups of arthropods the development cycle just won't neatly fit in the limited concepts defined by holo- and hemimetabolous development and historically the two terms larva and nymph have been used within a single group just to be able to better distinguish between the various stages. If I remember correctly this is the case for the likes of Odonata and Acari and probably some others too.
Within other groups, the concepts have always been "stretched" to make'm fit. What about Ephemeroptera with their visually very distinct larvae, not really a pupa, but a subimago instead. Or the "pupae" of most Neuroptera and Rhaphidioptera that are a bit of an "inbetweeny" between larva and imago and may walk/move freely about (in contrast to the pupae of beetles and butterflies etc.
All these examples very much stretch what you can "explain" with the holo/hemi concepts.
The Coccoidea are but another example of a difficult fit, with their males and females going through very different cycles, where compared to the females the youngsters could rightfully be named nymphs, whereas in lieu of the development of the males it would seem to make more sense talking about larvae and a pupa-stage. Concepts help us to simplify and grasp what's going on, but it seldom is just as simple as we would like it to be ;o) Posted 4 years ago, modified 4 years ago