Methodology

These pages combine a hand-written reference on 31 biting and stinging species with occurrence data from the GBIF biodiversity database. Species descriptions are written and reviewed by people; sighting counts and seasonality are generated from data and refreshed on a schedule. This page explains exactly which is which.

What is written by people

Every species description — how the bite looks, how it progresses, care advice, and the warning signs — is written and reviewed before publication, using public health and dermatology sources listed on our sources page. Nothing in the medical content is published without that review. Pages that have not been reviewed are not built at all, rather than published with a caveat.

What is generated from data

Sighting counts, the states where a species is recorded, and the months in which sightings concentrate come from GBIF, an international aggregator of verified biodiversity records. The dataset behind this site was last refreshed on 2026-07-27.

A page for a species in a specific state is only created when that state has at least 40 verified records for that species. That threshold currently produces 457 state-level pages. Where the data is thin, we do not generate a page — an empty template with a state name substituted in is not information.

What record counts do and do not mean

GBIF counts reflect how often a species is observed, reported and identified. They are shaped by where naturalists live, which species are photogenic, and which are the subject of surveillance programmes. A high count means a species is definitely present and commonly encountered. A low count does not prove absence, and no count predicts your personal risk of being bitten — particularly indoors, where bed bugs, fleas and lice do not depend on regional ecology at all.

Seasonality

Peak months are calculated from the monthly distribution of records, using state-level data where there is enough of it and national data otherwise. Months accounting for at least 10% of records are shown, up to four. This is observation seasonality, which tracks activity closely but is not the same thing.

What this site is not

It is not a diagnosis and cannot examine you. Bite identification from appearance alone is genuinely unreliable — clinicians treat pattern, timing, geography and exposure history as more informative than the mark itself, and so do we. Where a finding needs medical assessment, we say so plainly rather than suggesting a home remedy.

Updates and corrections

Occurrence data is refreshed periodically and the date is shown above. Medical content is reviewed at least annually and whenever guidance changes. Errors we find or that are reported to us are logged on the corrections page.