Emergence and return times in a colonial, cave-dwelling bat: age and sex differences driven by reproductive cycle
Bibliographic record
Abstract
The time that bats emerge, and subsequently return, from a colonial roost determines their maximum foraging period and influences their exposure to mortality risks. The order in which different age and sex cohorts emerge and return reflects variation in these cohorts’ resource requirements. The critically endangered Southern Bent-wing Bat (Miniopterus orianae bassanii) is an Australian insectivorous cave-roosting colonial bat. Resource limitation is hypothesised to have contributed to its decline, but may not affect all cohorts equally. We tagged and monitored 3,462 wild Southern Bent-wing Bats over seven years with Passive Integrated Transponder technology. To infer resource requirements of different cohorts over the reproductive cycle, we estimated cohort-specific peak emergence and return times and the frequency of nocturnal returns to the roost. The emergence and return behaviour varied with age, sex, and throughout the annual reproductive cycle. Although adult females and males behaved similarly during the non-breeding period (winter), females emerged significantly (12-21 minutes) earlier and returned (27-62 minutes) later than males during pregnancy, lactation, and weaning. Adult females were less likely than males to be detected overnight in the maternity roost while dependent young were present, suggesting that females prioritised maximising foraging over nocturnal nursing. When juveniles commenced flying, they delayed emergence until several hours after sunset (well after adults had departed the roost). During the 40-day weaning period, they progressively emerged earlier, such that by the end of this period they emerged with the adults, then subsequently foraged for longer than adults over winter. Passive monitoring of emergence and return behaviour in colonial bats can provide valuable data to infer cohort-specific resource requirements. Regular monitoring of a population’s emergence and return times potentially allows for the early detection of changes in resource requirements, and the use of PIT technology allows for the most vulnerable cohort(s) to be identified.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".