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Full-Text Articles in Life Sciences

Marine Invertebrates: Communities At Risk, Jennifer A. Mather Aug 2019

Marine Invertebrates: Communities At Risk, Jennifer A. Mather

Jennifer Mather, PhD

Our definition of the word ‘animal’ centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org) has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical …


What Is In An Octopus's Mind?, Jennifer Mather Aug 2019

What Is In An Octopus's Mind?, Jennifer Mather

Jennifer Mather, PhD

It is difficult to imagine what an animal as different from us as the octopus ‘thinks’, but we can make some progress. In the Umwelt or perceptual world of an octopus, what the lateralized monocular eyes perceive is not color but the plane of polarization of light. Information is processed by a bilateral brain but manipulation is done by a radially symmetrical set of eight arms. Octopuses do not self-monitor by vision. Their skin pattern system, used for excellent camouflage, is open loop. The output of the motor system of the eight arms is organized at several levels — brain, …


Geographic Variability Of Octopus Insularis Diet: From Oceanic Island To Continental Populations, Tatiana S. Leite, Allan T. Batista, Françoise D. Lima, Jaciana C. Barbosa, Jennifer A. Mather Aug 2019

Geographic Variability Of Octopus Insularis Diet: From Oceanic Island To Continental Populations, Tatiana S. Leite, Allan T. Batista, Françoise D. Lima, Jaciana C. Barbosa, Jennifer A. Mather

Jennifer Mather, PhD

A predator’s choice of prey can be affected by many factors. We evaluated various influences on population dietary composition, individual specialization and size of prey in Octopus insularis populations from 2 continental and 4 insular locations. We expected that habitat diversity would lead to diet heterogeneity. Furthermore, in keeping with MacArthur & Wilson’s (1967) theory of island biogeography, we expected that diet diversity would be lower around islands than on the coast of the mainland. Both predictions were confirmed when prey remains from octopus middens were examined. The 2 continental areas exhibited a richer habitat diversity and a wider variety …


Behaviour Development: A Cephalopod Perspective, Jennifer A. Mather Aug 2019

Behaviour Development: A Cephalopod Perspective, Jennifer A. Mather

Jennifer Mather, PhD

This paper evaluates the development of behaviour from the viewpoint of the intelligent and learningdependent cephalopod mollusks as a contrast to that of mammals. They have a short lifespan, commonly one to two years, and most are semelparous, reproducing only near the end of their lifespan. In the first two months of life, Sepia officinalis cuttlefish show drastic limitation on learning of prey choice and capture, gradually acquiring first short-term and then long-term learning over 60 days. This is paralleled by development of the vertical lobe of the brain which processes visually learned information. In the long nonreproductive adulthood, Octopus …


Mating Games Squid Play: Reproductive Behaviour And Sexual Skin Displays In Caribbean Reef Squid Sepioteuthis Sepioidea, Jennifer Mather Jun 2018

Mating Games Squid Play: Reproductive Behaviour And Sexual Skin Displays In Caribbean Reef Squid Sepioteuthis Sepioidea, Jennifer Mather

Jennifer Mather, PhD

Observation of the sexual interactions of Sepioteuthis sepioidea squid during the short reproductive stage of their lives showed a scramble competition system, with both male and female polygyny. Mature females were faithful to a specific location in the daytime, whereas males moved from group to group and formed short-term consortships with females. Males defended females from other males, particularly with an agonistic Zebra display. Male–female pairs exchanged Saddle-Stripe displays, after which males might display an on–off Flicker. There was considerable female choice. Only if a female responded to this display with a parallel Rocking action would she pair and would …


Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere Jun 2018

Cephalopods Are Best Candidates For Invertebrate Consciousness, Jennifer A. Mather, Claudio Carere

Jennifer Mather, PhD

Insects might have been the first invertebrates to evolve sentience, but cephalopods were the first invertebrates to gain scientific recognition for it.


An Invertebrate Perspective On Pain, Jennifer A. Mather Jun 2018

An Invertebrate Perspective On Pain, Jennifer A. Mather

Jennifer Mather, PhD

Although Key (2016) argues that mammals feel pain and fish do not, from an invertebrate perspective, it is obvious that the pain experience is shared by animals from a number of different animal groups.


Vigilance And Antipredator Responses Of Caribbean Reef Squid, Jennifer A. Mather May 2016

Vigilance And Antipredator Responses Of Caribbean Reef Squid, Jennifer A. Mather

Jennifer Mather, PhD

Antipredator responses, especially those of open-ocean squid, have been seldom studied in the natural environment. Sepioteuthis sepioidea, observed by snorkellers near the shore in early morning/late afternoon, produced an average of eight moves of over 1m per hour, apparently mostly antipredator behaviours. Close approaches by herbivorous parrotfish elicited no response in 74% of encounters; otherwise, squid produced agonistic zebra stripes or startle-mantle-dots skin patterns. Predatory bar jack fish caused flight but not zebra displays, and squid usually paled and fled quickly (66%) from snapper. The speed of approach was the best predictor for flight and display responses to snapper, …


Octopus Insularis (Octopodidae), Evidences Of A Specialized Predator And A Time-Minimizing Hunter, Tatiana S. Leite, Manuel Haimovici, Jennifer A. Mather May 2016

Octopus Insularis (Octopodidae), Evidences Of A Specialized Predator And A Time-Minimizing Hunter, Tatiana S. Leite, Manuel Haimovici, Jennifer A. Mather

Jennifer Mather, PhD

Shallow-water octopuses have been reported as major predators of motile species in benthonic marine communities, capturing their prey by different foraging techniques. This study assessed for the first time the feeding ecology, foraging behavior, and defensive strategy during foraging, including the use of body patterns, to construct a general octopus foraging strategy in a shallow water-reef system. Octopus insularis was studied in situ using visual observations and video recordings. The diet included at least 55 species of crustaceans (70%), bivalves (17.5%), and gastropods (12.5%); however, only four species accounted for half of the occurrences: the small crabs Pitho sp. (26.8%) …