Dataset of diverse evolutionary pathways shape cichlid egg size in Lake Tanganyika

Optimal egg size is a classic and important concept in life history theory. Here, we examined the ecological factors affecting egg size, using a comparative analysis of 83 cichlid species from Lake Tanganyika, which employ either a mouth-brooding or substrate-brooding. The two strategies differ substantially in regard to spatial limitations and food availability for offspring, potentially leading to divergent responses to the ecological factors influencing egg size. We observed a strong negative correlation between egg size and egg number in species that exhibit mouth-brooding, but not in substrate-brooding cichlids. Our results suggest that the importance of the relationship between clutch size and egg size varies substantially between these two types of parental care. Interestingly, in mouth-brooding species, we found that egg size increases when offspring exhibit external feeding behaviors (grazing behavior). We also demonstrate that substrate-brooding species with shorter periods of..., Egg size, clutch size (i.e., the number of eggs released during a single spawning event), and adult female body mass were measured in 47 mouth-brooding (belonging to 11 tribes) and 40 substrate-brooding cichlid species (belonging to 2 tribes), all endemic to Lake Tanganyika, in East-Central Africa. The sexually mature female specimens were obtained mainly from local fishermen and fish markets (n = 62 species, n = 161 individuals) and from field sampling using a fine-mesh gill net, hand nets, and SCUBA (n = 19 species, n = 73 individuals). The captured fish were euthanized by overdosing with anesthetic (MS-222, Wako Pure Chemical Industries) and stored in a freezer until measurements were taken. Given the relatively small sample size of females carrying mature eggs collected during the field survey, we also used samples stored at Osaka Metropolitan University (n = 10 species, n = 22 individuals) and the Hokkaido University Museum (n = 7 species, n = 13 individuals). Standard length (in m..., , ## Description of files and variables:

## File: data_cichlid.csv

**Description:** dataset including mouth- and substrate-brooding cichlids (n = 83 species).

##### Variables

* species: Species Code. The name corresponds to the phylogenetic tree data.
* samplesize: Number of mature females we caught.
* tribe: The tribe to which the species belonged.
* broodtype: brooding type (mouth- or substrate-brooding)
* care_sex: sexes mainly provide parental care 
* parentalcare_dulation: duration of parental care. For mouth-brooders, data collection for parental care period was not conducted; therefore, missing data are indicated as NA.
* guarding: sexes provide brood guarding (BI: biparental guarding, MG: maternal guarding, NG: no guarding)
* bodyweight: mean body weight of matured females (g)
* gonalweight: mean weight of ovary in matured females (g)
* clutchsize: the mean number of eggs in ovary
* eggsize: the maen size of matured egg in ovary (mm)
* SL: mean standard length (mm)
* gonadfree...,