LepIntercept Interactive Identification Key
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LepIntercept Dichotomous Keys
The LepIntercept Dichotomous Keys are written as traditional dichotomous keys with contrasting couplets. The keys are available as PDF files that can be downloaded and/or
printed for use without a computer. These keys are for advanced users - please visit the About page for information on using the LepIntercept keys.
NOTE: Due to the continuing spread of H. armigera in South America, exercise caution when attempting identifications of Helicoverpa from that continent. There are no morphological
characters to separate the larvae of H. armigera from H. zea. When in doubt, default to "Helicoverpa sp." instead of attempting a species-level ID. The following
keys may not reflect the most recent H. armigera distribution in South America.
Tips for examining larvae
Identifiers unfamiliar with Lepidoptera larvae should consult Stehr (1987) or Peterson (1948) for an overview of larval
morphology and study techniques. In addition, an illustrated section on Larval Morphology is provided
on this website. Larval characters can vary extensively, even in the same species, both between
instars and in the same instar. Most of the characters discussed in the fact sheets and used in the keys are based on late or last
instar larvae, and early instars of many species may be impossible to identify. When examining pinacula and setal number, be
sure to look at both sides of the larva, as some specimens are asymmetrical. When an asymmetrical individual is found, use the
highest number of setae when navigating the keys. Preservation of larvae can obscure characters, and even freshly preserved specimens may discolor and
make color or pattern characters useless. All of the larvae illustrated in the fact sheets are preserved, so these specimens may appear
very different from live and/or freshly collected individuals. It is also possible for pieces to break off specimens
preserved in alcohol, and occasionally setae or other structures (e.g., the anal comb) may be missing because of breakage. Any determination made
with the LepIntercept keys should be checked by an expert, and molecular analysis may be required to confirm identity in some cases.
Mandible and hypopharyngeal complex comparisons
Characters of the mandibles and hypopharyngeal complex can be quite useful in separating closely related species. In his review of larvae in the
Hadeninae (Noctuidae), Godfrey (1972) stated that the "most reliable characters are associated with the hypopharyngeal complex, left mandible, length
and shape of the dorsal abdominal setae, texture of the body integument, and the spacing of the metathoracic setae" (he found no difference between
left and right mandibles). Other authors (e.g., Ahola and Silvonen 2005, ; Beck 1999-2000; Passoa 1985) have illustrated mandibles and/or
the hypopharyngeal complex for a large number of species. Here we provide a pictorial comparison of these structures for the taxa treated in
LepIntercept. Please consult the Larval Morphology page for terminology related to these structures.