Nuptial flights below the equator

A January flight in Australia needs no British July record to explain it. Southern observations exist. A record from one Australian city, however, may tell you little about the same species elsewhere.

Dealate uses several kinds of evidence, and the six-month shift is only part of that process.

The app stores flight months in a common northern reference frame. For a southern location it shifts those months by six. July becomes January; December becomes June.

That can mean two different things. If the original observation came from Australia in January, it was shifted for storage and shifted back for display. The reader gets the original month. No northern flight has been used to predict an Australian one.

If the starting window came from northern evidence, displaying it in the south makes a biological assumption: that the local ants reproduce in the corresponding season. The arithmetic is exact. The assumption still needs checking against local observations.

Narendra and colleagues watched twelve Camponotus consobrinus nests in Canberra over eight years. They recorded 62 observation days and reported nuptial flights typically between December and March, with departures around sunset, usually a day before rain. Those are observations of Australian ants in Australia. The study's flight-timing results give both the location and the window.

They also show why a short calendar summary needs caution. December and January alone would cut that study's season short. The study followed Canberra nests; it did not measure flight seasons across Australia. Its dates cannot establish the full season for a population elsewhere.

We also derive genus-level windows from male-ant observations grouped by climate region. Some records come from iNaturalist observations whose identifications have not reached research grade. They can still carry a genus identification and a male annotation, which are useful to this particular analysis.

Those records improve the inputs, but a male photographed on a date is not necessarily a flight witnessed on that date. Uneven observer effort and uncertain identifications remain limitations. Worker sightings are an even weaker basis for flight timing.

The forecast uses regional windows where its evidence rules allow them. It also retains curated seasons and species records, and falls back to broader assumptions where stronger evidence is missing.

The written species guides have a separate set of regional genus estimates. These are labelled with the region they refer to. Adding one of those estimates to a guide does not change the live forecast. A genus estimate describes related ants in the named region. It is not a flight record for every species listed under that genus.

Dealate withholds fixed month claims on location pages inside 23.5 degrees north or south, and on species pages assigned its tropical category. The forecast also limits its use of generic calendar seasons there, while retaining some explicitly curated species or genus information.

That boundary is a modelling choice. Day length does change within the tropics, and tropical ants can have seasonal reproduction. What fails is the idea that every location can be understood by swapping a northern summer for a southern one. A local rainfall pattern or a dated flight observation can provide information that the six-month shift cannot. The tropical-season article explains why the app leaves some calendars blank.

When reporting a flight, include its date and location. Add the species name if you can identify it, or photographs if you cannot. A dated photograph of a flight is more useful than a claim that all the ants in a country flew that week. The methodology page explains how the weather and biological evidence contribute to the outlook.