DOI: 10.5061/dryad.60699
title: Data from: Complex life cycles: why refrain from growth before reproduction in the adult niche?

description: Organisms with complex life cycles occupy distinct niches as larvae and
 adults. One presumed advantage of this is the ability to exploit different
 resources successively throughout ontogeny. Various taxa, however, have
 evolved non-feeding, non-growing adult stages. We show theoretically that
 this counterintuitive 'no-growth' strategy is favored when the
 optimal larval size is greater than or equal to the optimal adult size for
 reproduction. We empirically investigated this in a group of parasitic
 worms (helminths). Helminths are transmitted trophically between hosts
 before reproducing in large, high-trophic-level hosts, and most undergo
 considerable growth as adults in their final host. Some well-studied
 tapeworm species (Schistocephalus, Ligula, and Digramma spp.) are notable
 exceptions; they reproduce semelparously without any growth in their final
 habitat (the gut of piscivorous birds). Using cross-species comparative
 analyses, we show that these tapeworms that do not grow in their final
 host (1) attain larval sizes in their last intermediate host (fishes) that
 are comparable to or larger than the adult sizes reached by tapeworms that
 do grow in the same adult niche (also piscivorous birds) and (2) are
 large, already as larvae, relative to the mass of their final hosts. These
 results are consistent with the idea that a massive larval size can make
 adult growth superfluous, and we discuss whether this likely applies to
 other complex life cycle taxa with nonfeeding, nongrowing adults.
description: mass_conv_indiv_measurementsThe file titled "mass_conv_indiv_measurements" contains data on the size of tapeworm individuals from 8 species. Four species grow in the final host (G) whereas the remaining four do not (NG). Some of these worms were from the Liverpool museum and their reference number is given. Worms were either measured live or preserved in formalin or ethanol. The worms were collected from either the intermediate host as plerocercoids or from definitive hosts as adults. Length, width, and mass are listed for all worms. Depth was also recorded for some worms. Area was calculated by multiplying length and width.mass_conv_species_avgsFor each of the species measured, the average length (mm), area (mm2), and mass (mg) were calculated. Additionally, this file contains data taken from the literature (see Online Table B1). Averages from our measurements are designated (orig), whereas the values from the literature are noted (lit).Larval_adult_sizeThe file titled "Larval_adult_size" contains data on the larval and adult size of tapeworms that grow in their piscivorous bird final host (G species). Lengths, widths, and areas (length x width) are given for each species. Areas were also converted to mass using relationships described in Online Appendix B. Finally, the source from which larval size was taken is listed (author, journal, volume, page numbers). Adult size was taken from Ryzhikov et al. (1985).Host_masses_mammalsTwo files contain information about the mass of cestode definitive hosts, "Host_masses_birds" and "Host_masses_mammals". For each cestode species, known hosts are listed with their mass. The mass of birds was taken from Dunning (1992). The mass of mammals from Smith et al. (2003) The average host size for each cestode is calculated. The host lists for cestodes in piscivorous birds were given by Ryzhikov et al. (1985). The host lists for cestodes in mammals were taken from the references from which size data were collected (see file "Host_size_regression.csv").Host_masses_birdsHost_size_regressionThe file "Host_size_regression" includes the size (length, width, area) of growing (G) and non-growing (NG) adult tapeworms in piscivorous birds and mammals. Log cestode area was also converted to log cestode mass as described in Online Appendix B. Data for cestodes of piscivorous birds were taken from Ryzhikov et al. (1985), whereas data for cestodes of mammals were taken from the primary literature (references are given for these tapeworms). The average host mass for a given cestode species is the average mass of known definitive hosts (see files "Host_masses_birds.csv" and "Host_masses_mammals.csv").