Invertebrate Biology

Repeatability of energy metabolism and resistance to dehydration in the invasive slug Limax maximus

by Juan Diego Gaitán-Espitia

Invertebrate Biology, Volume 131, Issue 1, pages 11–18, March 2012

Standard metabolic rate (SMR) and resistance to body dehydration (BD) are important physiological traits that have an... more Standard metabolic rate (SMR) and resistance to body dehydration (BD) are important physiological traits that have an effect on water balance and the amount of energy available for activity and production, and thus could contribute to variation in life history traits expressed across a range of environments. Few studies have tested whether SMR and BD show consistent between-individual variation in molluscs. Significant repeatability of SMR and BD indicates that the traits might be heritable and therefore a possible target for natural selection, so describing the repeatability of SMR and BD is important in studies of phenotypic variability. Here, we studied energy metabolism (body mass-corrected SMR) and the change in the scaling relationship of SMR and body mass in response to time between measurements in the giant garden slug Limax maximus. Limax maximus is one of the most invasive terrestrial molluscs, with a wide geographical distribution, and is considered an important pest of horticultural and agricultural crops. Our results show that L. maximus follows the expected relationship of increasing SMR with increasing mass, but the scaling exponent varies through time and is different from that described for other gastropods. We also found significant inter-individual variation in VCO2 Mean, VCO2 Min, VCO2 Max, and BD (τ=0.25, 0.29, 0.24, 0.22, p<0.05, respectively), and significant repeatability of body mass (τ=0.90). To our knowledge, this is the first comprehensive analysis of the repeatability of body mass-corrected SMR and BD in terrestrial slugs. Our results suggest that energy metabolism and water balance could potentially respond to selection.

Sleep in invertebrate

by Stefania Piscopo

open access

Purification of Visual Arrestin from Squid Photoreceptors and Characterization of Arrestin Interaction with Rhodopsin and Rhodopsin Kinase

by Walter Swardfager

Walter Swardfager, Jane Mitchell

Invertebrate visual signal transduction involves photoisomerization of rhodopsin, activating a guanine nucleotide... more Invertebrate visual signal transduction involves photoisomerization of rhodopsin, activating a guanine nucleotide binding protein (G protein) of the Gq class, iGq, which stimulates a phospholipase C, increasing intracellular Ca2+. Arrestin binding to photoactivated rhodopsin is a key mechanism of desensitization. We have previously reported the cloning of a retina-specific arrestin cDNA from Loligo pealei displaying 56–64% sequence similarity to other reported arrestin sequences. Here, we report the purification of the 55-kDa squid visual arrestin. Purified squid visual arrestin is able to inhibit light-activated GTPase activity dose-dependently in arrestin-depleted rhabdomeric membranes and associate with the membrane in a light-dependent manner. Membrane association can be partially inhibited by inositol 1,2,3,4,5,6-hexa- kisphosphate (IP6), a soluble analog of the membrane lipid phosphatidylinositol 3,4,5-triphosphate. In reconstitution assays, we demonstrate arrestin phosphorylation by squid rhodopsin kinase, a novel function among the G protein-coupled receptor kinase family. Phosphorylation of purified arrestin requires squid rhodopsin kinase, membranes, light-activation, and the presence of Ca2+. This is the first large-scale purification of an invertebrate arrestin and biochemical demonstration of arrestin function in the invertebrate visual system.

Effect of ocean acidification on the immune response of the blue mussel, Mytilus edulis

by Ruth N. Bibby

Surf and Turf: The use of marine and terrestrial resources in the Early Neolithic of Coastal South Portugal

by António Faustino Carvalho

Vaccines and crustacean aquaculture – a mechanistic exploration

by Ed Pope

Spring-fed Stream Benthic Macroinvertebrate Communities as Early Biological Indicators of Groundwater Tipping Point

by Rosemary Burk

Paper presented at the 2010 Annual World Water Week Conference in Stockholm. Co-authored with Jan Kallberg, Ph.D. and James H. Kennedy, Ph.D.. Page 349 in Abstract Volume.

Introduction/Problem Identification
In 2007, a 20-county area encompassing the Dallas-Fort Worth Metroplex was... more Introduction/Problem Identification
In 2007, a 20-county area encompassing the Dallas-Fort Worth Metroplex was designated by the State as a Priority Groundwater Management Area (PGMA) in need of implementing strategies for
groundwater conservation. The newly created PGMA’s population is expected to increase from 5.5 million in 2000 to 9.5 million by 2030 with projected water needs rising from 1,677 million m3
in 2000 to 3,034 million m3 by 2030 according to a study by Texas Commission on Environmental Quality (TCEQ). The Trinity Aquifer supplied 73% of the area’s groundwater in 2000, with the aquifer outcrop zone being highly susceptible to anthropogenic sources of contamination. Parker County is within the Upper Trinity Groundwater Conservation District (UTGCD) and is largely a rural area with many residents dependent upon private shallow, groundwater wells. Groundwater resources are under escalating pressure from urbanization, natural gas drilling, and predicted intensifying of droughts due to global climate change.

Regulatory effects of mussel (Aulacomya maoriana Iredale 1915) larval settlement by neuroactive compounds, amino acids and bacterial biofilms

by Tim Young

Published in 'Aquaculture' Volumes 322–323, 21 December 2011, Pages 158–168

Larval settlement responses of the ribbed mussel, Aulacomya maoriana Iredale 1915, were investigated after exposure to... more Larval settlement responses of the ribbed mussel, Aulacomya maoriana Iredale 1915, were investigated after exposure to various chemicals and mono-species bacteria. Identification of settlement inductive compounds assists in the elucidation of intermediary biochemical mechanisms involved in the neuronal control of settlement behaviour downstream from primary cue reception. Neuroactive compounds and amino acids (potassium ions, GABA, acetylcholine, l-Phenylalanine, l-Tyrosine, dopamine, epinephrine, l-Tryptophan, and 5-HTP) and planktonic bacteria, biofilms and biofilm exudates of Macrococcus sp. AMGM1, Bacillus sp. AMGB1, and Pseudoalteromonas sp. AMGP1 were tested for their abilities to induce larval settlement. Toxicity effects of each treatment also were simultaneously identified by recording larval mortalities. Results indicate that all chemicals used induced larvae to settle, with acetylcholine being the most effective (~ 24% at 10−6 M compared to < 2% in control assays). Toxicities of treatment compounds were low at optimal settlement inducing concentrations, except for l-Tryptophan (~ 32%) and GABA (~ 59%). Our data suggest that catecholamines (and their precursors) play an important role in the biochemical mechanisms of settlement for A. maoriana. While serotonin precursors did induce low levels of larval settlement at some concentrations, high toxicity responses to 5-HTP at 10−5 M, combined with complete settlement inhibition indicate that the mechanism of action may be more complex than can be elucidated in this study. Larval settlement responses to bacterial treatments were low for planktonic and biofilm phases across all three strains, and settlement inhibition was observed when larvae were exposed to biofilm exudates of all bacterial strains. Comparisons of A. maoriana responses to other endemic and worldwide distributed mussel species are provided as a means to highlight potential evolutionary differences in chemoreception mechanisms.

Variation in the structure of epifaunal invertebrate assemblages among coral hosts

by Jessica Stella

Stella, J.S., Jones, G.P., and Pratchett, M.S. (2010) Variation in the structure of epifaunal invertebrate assemblages among coral hosts. Coral Reefs, 29 (4). pp. 957-973

Abstract The high biodiversity of coral reefs is attributable
to the many invertebrate groups which live inmore Abstract The high biodiversity of coral reefs is attributable
to the many invertebrate groups which live in
symbiotic relationships with other reef organisms, particularly
those which associate with the living coral habitat.
However, few studies have examined the diversity and
community structure of coral-dwelling invertebrates and
how they vary among coral species. This study quantified
the species richness and composition of animals associated
with four common species of branching corals (Acropora
nasuta, A. millepora, Pocillopora damicornis, and Seriatopora
hystrix) at Lizard Island in the northern Great
Barrier Reef. One hundred and seventy-eight nominal
species from 12 different phyla were extracted across 50
replicate colonies of each coral host. A single coral colony,
approximately 20 cm in diameter, harbored as many as 73
individuals and 24 species. There were substantial differences
in invertebrate species composition among coral
hosts of different families as well as genera. Twenty-seven
species (15% of all taxa collected) were found on only one
of the four different coral species, which may potentially
indicate some level of specialization among coral hosts.
The distinct assemblages on different coral species, and the
presence of potential specialists, suggests invertebrate
communities will be sensitive to the differential loss of branching coral species resulting from coral reef
degradation.

Coral-associated invertebrates: diversity, ecological importance and vulnerability to disturbance

by Jessica Stella

Stella, JS, Pratchett, MS, Hutchings, PA and Jones, GP (2011). Coral-associated invertebrates: diversity, ecological importance and vulnerability to disturbance. Oceanography and Marine Biology: an Annual Review 49: 43-116.

The biodiversity of coral reefs is dominated by invertebrates. Many of these invertebrates live in close association... more The biodiversity of coral reefs is dominated by invertebrates. Many of these invertebrates live in close association with scleractinian corals, relying on corals for food, habitat or settlement cues. Given their strong dependence on corals, it is of great concern that our knowledge of coral-associated invertebrates is so limited, especially in light of severe and ongoing degradation of coral reef habitats and the potential for species extinctions. This review examines the taxonomic extent
of coral-associated invertebrates, the levels of dependence on coral hosts, the nature of associations between invertebrates and corals, and the factors that threaten coral-associated invertebrates now and in the future. There are at least 860 invertebrate species that have been described as coral associated, of which 310 are decapod crustaceans. Over half of coral-associated invertebrates appear to have an obligate dependence on live corals. Many exhibit a high degree of preference for one or two coral species, with species in the genera Pocillopora, Acropora and Stylophora commonly preferred. This level of habitat specialization may place coral-associated invertebrates at a great risk of extinction, particularly because preferred coral genera are those most susceptible to coral bleaching and mortality. In turn, many corals are also reliant on the services of particular invertebrates, leading
to strong feedbacks between abundance of corals and their associated invertebrates. The loss of even a few preferred coral taxa could lead to a substantial decline in invertebrate biodiversity and have far-reaching effects on coral reef ecosystem function. A full appreciation of the consequences
of further coral reef degradation for invertebrate biodiversity awaits a more complete description of the diversity of coral-associated invertebrates, the roles they play in coral reef ecosystems, their
contribution to reef resilience and their conservation needs.

Evidence of corallivory by the keyhole limpet Diodora galeata

by Jessica Stella

Urban physiology: city ants possess high heat tolerance

by Amanda Niehaus

An assessment of some molecular immune defences of the lesser octopus, Eledone cirrhosa (Mollusca: Cephalopoda)

by Magnus Johnson

The result of my MSc dissertation written in 1992 under the supervision of Chris J Secombes, Chris J Bayne and Peter r Boyle. Not published because a very similar more complete article appeared just as I completed my thesis. :-(

A survey of some immune functions of the haemolymph and circulating haemocytes of the lesser octopus, Eledone cirrhosa... more A survey of some immune functions of the haemolymph and circulating haemocytes of the lesser octopus, Eledone cirrhosa was carried out. Alpha-macroglobulin-like activity was found in the serum but not in the amoebocytes. Amoebocytes appeared capable of both weak phenoloxidase activity and the production of super-oxide radicals. It is suggested that, super-oxide and phenol immune functions are incompatible and that the presence of limited phenoloxidase activity in eledone amoebocytes may be an evolutionary relic.

The heart of Ciona intestinalis: eicosanoid-generating capacity and the effects of precursor fatty acids and eicosanoids on heart rate

by Ed Pope

Variety is the Spice of Life Histories: Comparison of Intraspecific Variability in Marine Invertebrates

by Molly Jacobs

Invertebrate Domestication: Behavioral Considerations

by Samuel M. ʻOhukaniʻōhiʻa Gon III

MACROFAUNA EN SUELOS DE BOSQUE Y PAJONAL DE LA RESERVA NATURAL PUEBLO VIEJO, NARIÑO, COLOMBIA

by Elkin A. Noguera-Urbano

The density and biomass of the edaphofauna are compared between ladder woodlands (Forest 1), woodlands in the drainage... more The density and biomass of the edaphofauna are compared between ladder woodlands (Forest 1), woodlands in the drainage area of a water source (Forest 2) and grassland, which are located at the same rank of heights (3.300-3.350 meters). The density is higher in Forest 2 than in Forest1 and the lowest is in Grassland soil, with medias of 1301, 581 and 293 ind/m². In the case of density of Gasteropoda and Diplopoda, there are significant statistical differences among Forest 2 and Grassland. The biomass is higher in grassland soil (51%) where Oligochaeta are a 68% of the total weight.

Can oxygen set thermal limits and drive gigantism?

by Wilco Verberk

PLoS One (2011) 6: e22610.

Background:
Thermal limits may arise through a mismatch between oxygen supply and demand in a range of animal... more Background:
Thermal limits may arise through a mismatch between oxygen supply and demand in a range of animal taxa. Whilst this oxygen limitation hypothesis is supported by data from a range of marine fish and invertebrates, its generality remains contentious. In particular, it is unclear whether oxygen limitation determines thermal extremes in tracheated arthropods, where oxygen limitation may be unlikely due to the efficiency and plasticity of tracheal systems in supplying oxygen directly to metabolically active tissues. Although terrestrial taxa with open tracheal systems may not be prone to oxygen limitation, species may be affected during other life-history stages, particularly if these rely on diffusion into closed tracheal systems. Furthermore, a central role for oxygen limitation in insects is envisaged within a parallel line of research
focussing on insect gigantism in the late Palaeozoic.

Methodology/Principal Findings:
Here we examine thermal maxima in the aquatic life stages of an insect at normoxia, hypoxia (14 kPa) and hyperoxia (36 kPa). We demonstrate that upper thermal limits do indeed respond to external oxygen supply in the aquatic life stages of the stonefly Dinocras cephalotes, suggesting that the critical thermal limits of such aquatic larvae are set by oxygen limitation. This could result from impeded oxygen delivery, or limited oxygen regulatory capacity, both of which have implications for our understanding of the limits to insect body size and how these are influenced by atmospheric oxygen levels.

Conclusions/Significance:
These findings extend the generality of the hypothesis of oxygen limitation of thermal tolerance, suggest that oxygen constraints on body size may be stronger in aquatic environments, and that oxygen toxicity may have actively selected for gigantism in the aquatic stages of Carboniferous arthropods.

IMMUNOLOCALIZATION OF CALCITONIN GENE-RELATED

by asma karami

Resistance among wild invertebrate populations to recurrent estuarine acidification

by Valter Amaral

Amaral V, Cabral HN & Bishop MJ, 2011 Estuar Coast Shelf Sci 93: 460-467. doi:10.1016/j.ecss.2011.05.024

Acid sulphate soils (ASS), which occur on floodplains worldwide, pose a significant threat to estuarine ecosystems. In... more Acid sulphate soils (ASS), which occur on floodplains worldwide, pose a significant threat to estuarine ecosystems. In laboratory and field experiments, naïve calcifying organisms that are exposed for even short periods (1e2 mo) to runoff from ASS suffer 80% mortality and slowed growth. Based on these observations we expected that sampling of wild oyster, gastropod and crab populations at sites close to and away from drains discharging ASS runoff would reveal more depauperate populations, of sparser and smaller-sized individuals at the more acidified sites. Sampling within three estuaries of New South Wales, Australia, confirmed that the oyster Saccostrea glomerata and gastropods (primarily Bembicium auratum) were less abundant at ASS-affected than reference sites. Nevertheless, crab abundances did not differ between the acidified and reference sites and impacts to bivalves and gastropods were far smaller than predicted. Although at ASS-affected sites gastropod populations were dominated by smaller individuals than at reference sites, oyster populations were skewed towards larger individuals. Even at ASS-affected sites, oyster and gastropod abundances were within the range encountered in estuaries that are not influenced by ASS runoff. Behaviour, long-term physiological acclimation or genetic selection may be responsible for differences in the responses of wild and naïve macroinvertebrates to acidification. Alternatively, wild populations may exhibit some recovery between the rainfall events that transport ASS runoff into estuaries, despite the persistently lower pH near outflow drains. Irrespective, this study suggests that at the population level, calcifying organisms display a certain degree of natural resistance
to recurrent disturbance from ASS runoff.