The Biogeography of Marine Invertebrate Life Histories

Abstract

Biologists have long sought to identify and explain patterns in the diverse array of marine life histories. The most famous speculation about such patterns is Gunnar Thorson's suggestion that species producing planktonic larvae are rarer at higher latitudes (Thorson's rule). Although some elements of Thorson's rule have proven incorrect, other elements remain untested. With a wealth of new life-history data, statistical approaches, and remote-sensing technology, new insights into marine reproduction can be generated. We gathered life-history data for more than 1,000 marine invertebrates and examined patterns in the prevalence of different life histories. Systematic patterns in marine life histories exist at a range of scales, some of which support Thorson, whereas others suggest previously unrecognized relationships between the marine environment and the life histories of marine invertebrates. Overall, marine life histories covary strongly with temperature and local ocean productivity, and different regions should be managed accordingly.

Does energy availability predict gastropod reproductive strategies?

“…Our findings of planktotrophic development in colder and more limited food regions, like the deep sea, do not support this. Similarly, our study is also in contrast to recent findings that planktotrophic development increases with increasing productivity [18,21] but matches those studies rspb.royalsocietypublishing.org Proc. R. Soc.…”

Unravelling anisogamy: egg size and ejaculate size mediate selection on morphology in free-swimming sperm

“…By now showing that egg size reciprocates as an agent of selection on sperm, we infer that the evolutionary fates of the sexes are coupled by interactions between gametes at both pre-and postzygotic stages of the life history. Moreover, the evolutionary diversification of egg size spans an astonishing several orders of magnitude among extant metazoans, and is usually attributed to environmental heterogeneity in postzygotic selection [67]. The possibility that sperm evolution has been harnessed to this process implies that a key next step will be to look for signs of gamete coevolution in the deeper evolutionary history of this group.…”

Temporal variation in intertidal community recruitment and its relationships to physical forcings, chlorophyll-a concentration and sea surface temperature

“…These differences can generate responses from both adults and the early life stages of invertebrates, altering the rates of growth and reproduction (Phillips 2002, Narváez et al 2007. Laboratory experiments show that variation in Chla influences daily survival of larvae and settlers (Marshall et al 2012). In contrast, in natural environments, the changes in Chla at shorter temporal scales (hours to few days) may not be able to impact the response time of the biological processes of settled consumers (e.g., Coale et al 1996, Sanford and, or the changes in Chla may not be drastic enough to impact larval growth.…”