When desperation overcomes fear, ecosystems may be reshaped

This blog post was written by QBIC sophomore, Brian Ho.

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Heithaus, M., Frid, A., Wirsing, A., Dill, L., Fourqurean, J., Burkholder, D., Thomson, J. & Bejder, L. (2007). State-dependent risk-taking by green sea turtles mediates top-down effects of tiger shark intimidation in a marine ecosystem. Journal of Animal Ecology, 76, 837-844.

Predators and prey have always been at odds with one another. Both dance to the tune of essential components of the natural order: one seeks to live and pass on its genes, the other fancies a satisfying meal. The result is a continuous, dynamic arms race in all corners of the globe. Predators become better hunters, and prey better at evading them. Ecosystem equilibria are thus maintained through the balancing of these interactions.

Yet the relationships between different species are often quite complex. Predators are capable of affecting their ecosystems by influencing the behavior of their prey, in addition to actually eating them. These non-lethal effects of predation are often dependent upon the state, or physical body condition, of the prey. They are also usually overlooked in community dynamics studies – i.e. the study of how communities change over time as a result of species interactions (Boundless, 2014).

The Secrets of Seed Dispersal: Hidden In Turtle Poop

This post was written by QBIC sophomore Emmanuel Medrano.

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Liu, Hong, Steven G. Platt, and Christopher K. Borg. "Seed Dispersal by the Florida Box Turtle (Terrapene carolina bauri) in Pine Rockland Forests of the Lower Florida Keys, United States." Oecologia 138.4 (2004): 539-46. 

For animals, it is easy to move between different locations. If they find themselves in an environment they do not like, they can simply migrate to other areas where they may be able to find more food or mates. As a result, populations of animals can occupy a great area of land. Plants, on the other hand, are incapable of this sort of dispersion. As they say, “the apple does not fall far from the tree”. However, plants are in luck, because animals can and do eat apples and other types of fruits. While in the stomach, the fruit becomes digested but the seed remains intact. This seed can then be excreted by the animal, and voila, the seed has moved.

Extrafloral Nectar: Understanding Ant bodyguard pay.

This post was contributed by QBIC Sophomore, Renata Gallegos.

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Jones IM and Koptur S (2015). Dynamic extrafloral nectar production: The timing of leaf damage affects the defensive response in Senna mexicana var. chapmanii (Fabaceae). American Journal of Botany 101(1): 58-66.

Plants are sessile organisms incapable of movement and unable to escape their predators, of which they have many. If left unprotected, particular plants can lose up to 40% of their biomass to a single species of insect alone. To compensate for their immobility, plants have developed a variety of indirect defenses, one such example being extrafloral nectar (EFNs). An EFN is a solution of sugars secreted by glands found outside of the flower. While a large variety of arthropods (animals such as insects) are attracted to this sweet solution, its potential is truly exploited only when discovered by ants. EFN is produced for the ants in exchange for their services in fending off herbivores, a widespread mutualism. Understanding the factors that affect this phenomenon is essential to understanding how plants manage their defenses, and that is exactly what scientists in Florida International University are doing.

Individual Specialization in the Lionfish

This post was written by QBIC sophomore, Brianna Almeida.

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Layman CA., Allgeier JE.(2012) Characterizing trophic ecology of generalist consumers: a case study of the invasive lionfish in The Bahamas. Marine Ecology Progress Series. 448:131-141

Generalist species are organisms that have a wide range of diet and habitat. As a result, many invasive species are also generalist species. Invasive species are able to colonize new habitat, usually through human activities, and alter the food web by consuming the native species of that habitat. Native or endemic species are usually specialist species which specialize in obtaining one type of food source. This causes competition with endemic predators, resulting in the generalists being the “winner species”. This spread of generalist species is known as biotic homogenization.

Highly dynamic fission-fusion species can exhibit leadership when traveling

This post was written by QBIC sophomore, Mariluz Soula.

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Lewis JS, Wartzok D, Heithaus MR. (2011) Highly dynamic fission-fusion species can exhibit leadership when traveling. Behavior Ecology Sociobiology 65: 1061-1069

Leadership in tight-knit social groups is known to enhance the fitness of the entire group. Leadership by specific individuals usually occurs in species groups that are stable and related, and that inhabit complex habitats (Payne, 2003). However, leadership has not been studied in fission-fusion groups, or social groups that change in size and composition as time passes. In a species exhibiting fission-fusion dynamics, the group might disperse to forage during the day (fission), then reunite to sleep in the same place (fusion). Although these groups tend to be unstable, complex habitats may allow leadership to develop regardless. Leaders may have variable effects: they may lead the group to areas rich in resources but may also lead the group away from forage sites (King et al., 2009). Leaders of fission-fusion groups may also influence group size and may actually select individuals from the group that will maximize the leader’s fitness since these types of species frequently change in composition and size (Conradt & Roper, 2005).