The number of offspring an organism can produce is a key component of its evolutionary fitness and life-history. This number differs widely between organisms, and its variation is the foundation for several hypotheses about life-history evolution, including the prediction that there is an evolutionary trade off between the number of offspring and their size. In insects, the number of egg-producing compartments in the ovary, called ovarioles, has been used as a proxy for potential offspring number in the study of life-history. Here we present a database of 3,355 descriptions of insect ovariole number, with records for 2,103 unique insect species from 28 hexapod orders. The dataset includes insects with a total adult ovariole number of 1 as well as insects with more than 10,000 ovarioles. We created this database by searching for descriptions of insect ovaries from the primary literature. We matched the taxa in this database to the currently accepted scientific names in taxonomic and genetic databases, which will facilitate the use of this data for testing hypotheses in offspring number evolution.

We searched the published literature for references to insect ovariole number using a predetermined set of 131 search terms, entered into Google Scholar (scholar.google.com) between June and October of 2019. Each search term consisted of an insect taxonomic group and the words “ovariole number”. This list was created to include all insect orders, many large insect families, and groups well-represented in the insect egg dataset. For each search term, we evaluated all publications in the first page of results (ten publications). For 61 search terms that had a large number of informative hits, significant representation, or that corresponded to very speciose groups, we evaluated an additional 20 publications. If a publication reported ovariole number for one or more insect species, we recorded the following information: (1) genus, (2) species name, when available, (3) taxonomic order, (4) sample size, when available, (5) ovariole number, and (6) additional notes (e.g. for eusocial insects, whether the observation was made in a reproductive or non-reproductive individual). 

Ovariole number was recorded as either an average with deviations, a range, or a single total value, with priority for recording given in that order when multiple data types were available. Ovariole number was recorded as the total number of ovarioles per female, summing over both the left and right adult ovaries. When authors reported ovariole number from a single ovary, the total value was calculated by doubling the reported value. When authors described differences between the two ovaries, this information was recorded in an additional notes section. Using this approach, we gathered 3,355 records for ovariole number from 460 publications, provided here as well. We matched the scientific names to additional taxonomic information using the software TaxReformer,  and found additional taxonomic data for 3,252 of the 3,355 records. We verified that TaxReformer had found a valid match for the record by comparing the originally recorded taxonomic order to the order populated by online databases, and flagged 22 taxonomic records for which these values did not match.

Ovariole Number Dataset

A tab delimited dataset of insect ovariole number from the published literature, including notes on data collection.

ovariole_number_data.tsv

Ovariole Number Taxonomic Information

A tab delimited dataset of taxonomic information, retrieved with TaxReformer: https://github.com/brunoasm/TaxReformer. Entries can be matched to those in the ovariole number dataset by their unique ID number.

ovariole_number_taxonomic_info.tsv

Ovariole Number Bibliography (BibTeX format)

A bibtex file of sources cited in the ovariole number dataset. References listed here can be matched to entries in the ovariole number dataset by their unique bibliographic identifier (e.g. Iwata1958).

bibliography_egg_dataset.bib

Ovariole Number Bibliography (PDF format)

A formatted bibliography of sources cited in the ovariole number dataset.

bibliography_egg_dataset.pdf