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Does Energy Availability Predict
Gastropod Reproductive Strategies?
Craig R.McClain
National Evolutionary Synthesis Center...
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Prov...
Liferequiresenergy
Veined Octopus (Amphioctopus marginatus) eating a crab
Threedistinct
types of energy !
affect biological
systems
1. solar radiation in the form of
photons!
2.thermal kinetic ene...
Planktotrophic: feed in the plankton
during their larval stage and are
considered to have longer dispersal
potential
Lecit...
Thermal kinetic energy and chemical potential energy
are posited to influence reproductive strategies
Low
Temp
Food
%Plankt...
Thermal kinetic energy and chemical potential energy
are posited to influence reproductive strategies
Low
Food
%PlanktonicL...
Hermaphroditic nudibranchs,
Siphopteron sp. nov., from the
Great Barrier Reef !
!
R. Lange, J. Werminghausen and N. Anthes...
Thermal kinetic energy and chemical potential energy
are posited to influence reproductive strategies
Low
Food
%Hermaphrodi...
For 189 !
gastropod families !
collected data on!
!
larval development !
(dispersing v. not)!
!
& hermaphroditism !
(prese...
Analyses
• Binary and binomial regression models were implemented in R using the package
MCMCglmm
• uninformative priors a...
sqrt (Median Carbon Flux)
ProbabilityofOccurrence
Mixed
Direct
Lecithotrophic
Planktotrophic
50 150 2500.00.51.0
the odds ...
50 150 2500.00.51.0
sqrt (Median Carbon Flux)
ProbabilityofOccurrence
Hermaphroditic
Non-Hermaphroditic
Result opposite of...
0.0 0.5 1.0 1.5 2.0
Caenogastropoda
Cocculiniformia
Eupulmonata
Heterobranchia
Neritimorpha
Patellogastropoda
Vetigastropo...
Planktotrophic larvae increases!
Direct development decreases!
with decreasing productivity. !
Thus, low energy availabili...
Acknowledgments
Coauthors: Ryan Filler (Duke
University) and Josh Auld (West
Chester University)
!
Statistical Guidance: C...
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Does Energy Availability Predict Gastropod Reproductive Strategies?

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Does Energy Availability Predict Gastropod Reproductive Strategies?

  1. 1. Does Energy Availability Predict Gastropod Reproductive Strategies? Craig R.McClain National Evolutionary Synthesis Center, Duke University McClain et al. Proceedings of the Royal Society B, in press Two female bubble-rafting violet snails, Janthina exigua. Egg capsules are attached to the underside of the floats.
  2. 2. You$are$free$to:$ Copy,$share,$adapt,$or$re2mix;$ Photograph,$film,$or$broadcast;$ Blog,$live2blog,$or$post$video$of;$ Provided$that:$ You$a?ribute$the$work$to$its$author$and$respect$the$rights$and$licenses$associated$with$its$components.$ @DrCraigMc #snailsex
  3. 3. Liferequiresenergy Veined Octopus (Amphioctopus marginatus) eating a crab
  4. 4. Threedistinct types of energy ! affect biological systems 1. solar radiation in the form of photons! 2.thermal kinetic energy as indexed by temperature! 3.chemical potential energy stored in reduced carbon compounds Clarke & Gaston (2006) Proc Roy Soc B
  5. 5. Planktotrophic: feed in the plankton during their larval stage and are considered to have longer dispersal potential Lecithotrophic: larvae derive nourishment from yolk and are non- feeding and are considered to have longer dispersal potential Direct: young develop directly into the adult form without a larval phase and typically have limited dispersal potential
  6. 6. Thermal kinetic energy and chemical potential energy are posited to influence reproductive strategies Low Temp Food %PlanktonicLarvae slow larval growth long larval duration fast larval growth short larval duration Predation High Temp Food Thorson
  7. 7. Thermal kinetic energy and chemical potential energy are posited to influence reproductive strategies Low Food %PlanktonicLarvae planktonic larvae cheap minimize larval/adult competition dispersal phases allow for bet hedging direct development expensive retention of larvae favored High Food
  8. 8. Hermaphroditic nudibranchs, Siphopteron sp. nov., from the Great Barrier Reef ! ! R. Lange, J. Werminghausen and N. Anthes. Cephalo-traumatic secretion transfer in a hermaphrodite sea slug. Proceedings of the Royal Society B. Published online November 13, 2013. doi: 10.1098/rspb.2013.2424.! ! J.M. Koene et al. A syringe-like love dart injects male accessory gland products in a tropical hermaphrodite. PLOS ONE. Vol. 8, July 2013, p.e69968. doi:10.1371/journal.pone.00e69968
  9. 9. Thermal kinetic energy and chemical potential energy are posited to influence reproductive strategies Low Food %Hermaphroditism density low mate availability low density high mate availability high High Food Abundance
  10. 10. For 189 ! gastropod families ! collected data on! ! larval development ! (dispersing v. not)! ! & hermaphroditism ! (present v. absent)
  11. 11. Analyses • Binary and binomial regression models were implemented in R using the package MCMCglmm • uninformative priors and uniformly low levels of belief • Model chains were run for 500,000 iterations with a burn-in of 200,000 iterations and thinning intervals of 100 iterations. • To evaluate convergence, we assessed the mixing of Markov chain Monte Carlo (MCMC) chains • Chemical energy available to the gastropods was estimated as particulate organic carbon (POC) flux (g of C m−2 year−1) based on the Lutz et al. (2007) model. • Temperature data was gathered from the NODC database (Locarnini et al. 2010). • For each family, we quantified the median and standard deviation of carbon flux and temperature over their known latitudinal and depth ranges. • Taxonomic Order—from the most current taxonomy for Gastropoda (Bouchet & Rocroi 2005) —was included as a random effect to account for the possible effects of shared phylogenetic history in our model. A more explicit estimation of phylogenetic covariance was not possible due to the current lack of a comprehensive molecular phylogeny for this clade.
  12. 12. sqrt (Median Carbon Flux) ProbabilityofOccurrence Mixed Direct Lecithotrophic Planktotrophic 50 150 2500.00.51.0 the odds of having planktotrophic larvae versus direct development decreasing by 1% with every one- unit increase in the square root of carbon flux Opposite of that predicted by Thorson
  13. 13. 50 150 2500.00.51.0 sqrt (Median Carbon Flux) ProbabilityofOccurrence Hermaphroditic Non-Hermaphroditic Result opposite of prediction! ! Relationship disappears when accounting for taxonomic relatedness.
  14. 14. 0.0 0.5 1.0 1.5 2.0 Caenogastropoda Cocculiniformia Eupulmonata Heterobranchia Neritimorpha Patellogastropoda Vetigastropoda Log Median POC flux (g of C m-2 year-1) Distribution Basal metabolic rates of nudibranchs are highest among gastropods.! ! Metabolically expensive to be a simultaneous hermaphrodite
  15. 15. Planktotrophic larvae increases! Direct development decreases! with decreasing productivity. ! Thus, low energy availability is selecting for adaptations for energy conservation or bet heeding in a patchy environment.! ! The result for hermaphroditism is opposite of prediction, ! decreases not increases with decreasing energy availability ! and likely related to shifts in metabolic demand not life reproductive strategy Does Energy Availability Predict Gastropod Reproductive Strategies?
  16. 16. Acknowledgments Coauthors: Ryan Filler (Duke University) and Josh Auld (West Chester University) ! Statistical Guidance: Carlos Botero (NC State University) ! Funding: National Evolutionary Synthesis Center (NSF Grant #EF-0905606) National Evolutionary Synthesis Center

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