About once a week, my legges taken me (in a Middle English sort of way) over to lunch in the common room of our Department of Agriculture, where a kindly member of staff leaves copies of journals for us to read. One that has taken my interest recently is the June 2009 issue of Trends in Ecology and Evolution, in which I have read two reviews whose contents I will summarize. The first of these is:
The jellyfish joyride: causes, consequences and management responses to a more gelatinous future
by Anthony J. Richardson, Andrew Bakun, Graeme C. Hays and Mark J. Gibbons http://dx.doi.org/10.1016/j.tree.2009.01.010
Abstract: Human-induced stresses of overfishing, eutrophication, climate change, translocation and habitat modification appear to be promoting jellyfish (pelagic cnidarian and ctenophore) blooms to the detriment of other marine organisms. Mounting evidence suggests that the structure of pelagic ecosystems can change rapidly from one that is dominated by fish (that keep jellyfish in check through competition or predation) to a less desirable gelatinous state, with lasting ecological, economic and social consequences. Management actions needed to stop such changes require tactical coping strategies and longer-term preventative responses based on fundamental and targeted research on this understudied group.
Jellyfish outbreaks don’t occur everywhere. In some places human predation on fish-eating fish has allowed plankton-eating fish to multiply and consume the jellyfish larvae. But in others, the bigger fish that eat the jellyfish have gone, allowing the jellies to eat the young fish. Jellyfish are tough creatures that can survive in environments that have been rendered hostile by fertilizer run-off or climate-related environmental change. The authors suggest that:
The potentially durable switch to a jellyfish-dominated system is reminiscent of the ancient, rudimentary ecosystems of the Cambrian, and has convinced some authors and that human stressors are propelling marine ecosystems ‘way back to the future’
and quote Weiss, K.R. in A primeval tide of toxins (LA Times, 30 July 2006):
‘My kids will tell their children: eat your jellyfish!’
The second of these reviews is:
Unicolonial ants: where do they come from, what are they and where are they going?
Heikki Helanterä, Joan E. Strassmann, Juli Carrillo and David C. Queller http://dx.doi.org/10.1016/j.tree.2009.01.013
Abstract: Unicolonial ant populations are the most extensive cooperative units known in nature, forming networks of interconnected nests extending sometimes hundreds of kilometers. Within such a supercolony, worker altruistic behavior might be maladaptive, because it seems to aid random members of the population instead of relatives. However, recent genetic and behavioral data show that, viewed on a sufficiently large scale, unicolonial ants do have colony boundaries that define very large kin groups. It seems likely that they are family groups that continue to express their kin-selected behavior as they grow to extreme sizes. However, at extreme sizes, kin selection theory predicts that these behaviors are maladapted and evolutionarily unstable, a prediction that is supported by their twiggy phylogenetic distribution.
In other words, these huge ant colonies seem to be an evolutionary dead end. Might I, indulging in a little ‘Social Darwinism’, be so bold as to suggest that mega-corporations and giga-banks are likewise on the road to ruin?