A queen in a paperwasp colony largely stays in the dark. The worker wasps, who fly outside to seek food and building materials, see much more of the world around them. A new study indicates that the brain regions involved in sensory perception also develop differently in these castes, according to the different behavioral reliance on the senses. The study is published in Behavioral Ecology and Sociobiology.

“The wasps in different castes within a colony don’t differ much genetically. The differences we see show the signature of the environment on brain development,” said Sean O’Donnell, PhD, a professor in Drexel University’s College of Arts and Sciences who led the study.

O’Donnell’s team found that the queen wasps had smaller brain regions for processing visual information than the workers in their own colonies. The pattern held across most of the 12 species of paperwasps they studied.

Most other research in how animals’ environments affect their nervous systems – known as neuroecology – emphasizes comparisons between the brains of different species with diverse lifestyles and behaviors, such as comparisons between nocturnal and diurnal species of birds or bats.“The strong behavioral and ecological differences between individuals within insect colonies make them powerful tools for studying how individual brain differences come about, and their functional significance,” O’Donnell said.

To test how queen-worker brain differences come about, O’Donnell’s team also compared differences in queen and worker wasps’ brain development across different wasp species they studied.

In species where adult wasps fight for the queen position, it would make sense for the caste brain differences to be less pronounced than in species where adult wasps emerge with their caste roles already established – if brain development followed a preordained program for each assigned role.

Instead, the researchers found larger differences between worker and queen wasp brains in species where adult wasps fought for dominance – a finding that suggests brain plasticity, or development in adulthood in response to environmental and behavioral needs.

O’Donnell noted that sampling juvenile wasps at multiple stages of brain development would help confirm the finding suggested by his study that only looked at adult wasp brains.

– See more at: http://drexel.edu/now/archive/2014/January/Wasp-Castes-Sensory-Brain-Structures/

Hurricane Sandy landed right on top of Dr. Tracy Quirk’s wetland monitoring stations – but it wasn’t all bad news.

Quirk, an assistant professor in the Department of Biodiversity, Earth and Environmental Science at Drexel University, had been performing wetland research for several years at monitoring sites in Barnegat and Delaware Bays in New Jersey. Recording devices installed at these sites continuously measured water level and salinity for a wide range of wetland studies at Drexel and the Academy of Natural Sciences of Drexel University.

As Sandy hit and water levels rose, those measurements continued.

“We have continuous data on how long these areas were flooded and how high the water rose at these sites,” said Quirk.

It was a stroke of good luck to have captured detailed measurements during a storm of this rare magnitude. Quirk recognized that the data could provide new answers to the questions she had been investigating about how wetland ecosystems sustain themselves and function. Now she could also learn how marshes responded to the severe disturbance effect of the storm.

“The prospect of future storms of this magnitude suggests that we will need to understand their effects on ecosystem dynamics as part of the ‘new normal,’” Quirk said.

In February she began working on an intensive year-long project, funded by the National Science Foundation, to evaluate ecosystem processes in New Jersey’s salt marshes before, during, and for a year following Hurricane Sandy. Quirk is beginning to analyze findings from the study now.

Good News/Bad News: Coastal Marshes Protective from Worse Flooding, But Findings Suggest They’re Diminishing and Sinking

There was some good news from the marshes: Although some water-level recorders were over-topped and stopped recording (making it difficult to use direct measures of the water height), there was evidence of marsh swelling during the storm. That swelling is an indication of marshes’ ability to absorb some of the storm surge – which, in hard-hit urban areas, had resulted in high water marks up to seven feet during Hurricane Sandy. Quirk points out that resilient, healthy wetlands near coastal areas have a key role in protecting local communities from hurricane-induced storm surges and flooding.

“Imagine having a marsh in front of your house instead of concrete,” Quirk said. “Paved areas make flooding worse because water has nowhere to go.”

In her post-Sandy research, Quirk was interested in finding out whether the storm affected how the marshes sustain themselves. The disturbance of an intense storm could alter the delicate equilibrium between flooding, vegetation growth and sediment deposits in wetland ecosystems – either temporarily or long-term.

That’s where the bad news comes in. As she works through the data analysis this fall, Quirk said she hasn’t found much sign of sediment deposits, before or after the hurricane struck. Sandy had the potential to deposit a lot of sediments, fast, which would have been good for building up wetlands. Hurricane Irene in 2011 had been associated with a bump up in wetland accretion by several millimeters at a number of locations in the region – a bonus growth equivalent to the amount that typically accrues in an entire year.

“Sediment-limited systems like coastal lagoon marshes largely depend on deposition by storms to vertically adjust elevation, so they don’t sink relative to sea level,” Quirk said. “In places where we have ongoing monitoring, the evidence suggests that some sites are subsiding – sinking below the surface – rather than increasing elevation at a rate similar to local sea level rise. Surface deposition would be a good thing for these marshes.”

Any number of reasons could explain why those hoped-for sediment deposits didn’t materialize, she said. Maybe the unusually high tide during Hurricane Sandy caused less suspension of sediments in the storm-surge waters. Or maybe the storm water did carry sediments and plant debris, but dropped them on the barrier island or inland along the tree line and not at her sampling sites in the marsh interior.

Essential to Protect Coastal Marshes from Subsiding into Water

Whatever the reason, Quirk’s findings point to cause for continued concern over the coastal marshes’ future.

“These salt marshes provide a number of extremely valuable ecosystem services and benefits to society,” she said. Storm surge protection is just one of these. Coastal marshes also provide excellent habitat for commercially and recreationally important fish and shellfish, especially as a nursery ground for these animals. They’re also important for storing, transforming and removing nutrients that can be harmful to the aquatic ecosystems.

The areas of tidal wetlands remaining in New Jersey have been sharply reduced in proportion to the past, with surrounding areas built up with bulkheads and other development – making the remaining wetlands all the more crucial to protect because they cannot shift inland.

“With accelerating sea level rise, it is unknown how many of these marshes are going to be able to keep up because they are dependent on plant growth, which is a slow process,” Quirk said.

“Since 2010, the northern area of Barnegat Bay and the marsh on the bayside of the barrier island at Island Beach State Park is converting before our eyes from marsh to open water.”

– See more at: http://drexel.edu/now/archive/2013/October/Hurricane-Sandy-Marsh-Impacts-One-Year-Later/

The second-most-common catch on Costa Rica’s longline fisheries in the last decade was not a commercial fish species. It was olive ridley sea turtles. These lines also caught more green turtles than most species of fish.

These findings and more, reported in a new study in the Journal of Experimental Marine Biology and Ecology, indicate that the Costa Rican longline fishery represents a major threat to the survival of eastern Pacific populations of sea turtles as well as sharks.

The researchers argue that time and area closures for the fisheries are essential to protect these animals as well as to maintain the health of the commercial fishery.

The research was conducted by a team from Drexel University, the Costa Rican non-profit conservation organization Pretoma and a U.S. non-profit working in Costa Rica, The Leatherback Trust.

The researchers used data from scientific observers on longline fishing boats who recorded every fish and other animal caught by the fishermen from 1999 to 2010 and the locations of the captures and fishing efforts. Those data provided the basis for a mathematical analysis of the fishery resulting in maps of geographic locations and estimates of the total number of captures of sea turtles in the entire fishery.

Stark threats to sea turtles, including nesting populations

The most commonly targeted fish, mahi mahi, was also the most common species caught in the Costa Rican longline fishery.

But the researchers were surprised by their finding that olive ridley turtles, internationally classified as vulnerable, were the second-most-common species caught.

They estimate that more than 699,000 olive ridley and 23,000 green turtles were caught during the study period (1999 to 2010).

Although about 80 percent of captured sea turtles are released from longlines and survive the experience, at least in the short term, long-term impacts are not yet adequately measured.

“It is common to see sea turtles hooked on longlines along the coast of Guanacaste in Costa Rica. We can set some free but cannot free them all,” said Dr. James Spotila, the Betz chair professor of environmental science in the College of Arts and Sciences at Drexel. “The effect of the rusty hooks may be to give the turtles a good dose of disease. No one knows because no one holds the turtle to see if its gets sick.”

Spotila, a co-author of the study, has been studying sea turtles on the Pacific coast of Costa Rica with colleagues and Drexel students, for 23 years.

The researchers also noted that even a few deaths of reproductive females may have a significant toll—particularly  when longline operations are held in shallow waters of the continental shelf close to nesting beaches.  They reported that declines in olive ridley nesting populations in Ostional, where massive synchronous nesting occurs, were associated with these captures.

Catching more and smaller fish signals an unsustainable fishery, sharks at particular risk

In addition to mahi mahi, other species targeted in the Costa Rican longline fishery were tunas, sharks and marlins.

The researchers observed that longlines caught large numbers of mahi mahi, silky sharks, stingrays, sailfish and yellowfin tuna.

But the fishing patterns showed that shark populations have declined in numbers and sharks have become smaller over 11 years.  Adult sharks were generally small, and juvenile sharks alarmingly abundant, suggesting that some shark species were being overfished: Overall, only 14.6 percent of the abundant silky sharks observed during the study period were sexually mature.  In 2010, the last year of the study, average fork length of silky sharks was 97 cm, far below the observed 144 cm average for mature adults. These decreases in size of silky sharks through time indicated a reduction in relative numbers of adults in the population.

Additionally, many small blacktip sharks were captured in an area near the Osa Peninsula, indicating that fishing was occurring at a nursery ground for that species.

The small size of adult sharks and large numbers of juveniles captured suggest that species are being overfished.

In addition to these indicators of overfishing of sharks, the researchers warned of broader uncertainty about the health of the fishery. They said that capture of large numbers of mahi-mahi does not guarantee that that population is sustainable because the available data can not determine if mahi mahi will remain abundant or decline.

Based on these findings, the researchers caution that that populations of fish affected by the Costa Rican longline fishery may be in danger of collapse and that there are insufficient scientific data to predict whether and when such a collapse will occur and in what species.

How to manage the fishery and save the turtles

To better manage the fishery and protect the threatened and endangered species of sea turtles in Costa Rica, the researchers argue that policymakers in Costa Rica must enforce time and area closures for longline fishing.

They criticize both the fishing industry and INCOPESCA, the fisheries management agency of the government, for failing to recognize that the fishery is unsustainable and failing to enforce existing fisheries laws, such as those against landing of shark fins and harming of sea turtles.

“INCOPESCA has failed to adequately study and regulate the fishery in Costa Rica for many years. It does not even enforce national laws. Board members have serious conflicts of interest because they are commercial fishermen,” said Randall Arauz, president of Pretoma and a world recognized leader in marine conservation. “Until INCOPESCA is reformed in such a way that the Board of Directors is eliminated and its mission is to defend the public interest, neither the fish nor the turtles will be safe.”

Arauz, a co-author of the study, has been studying sea turtles and fisheries in Costa Rica for more than 30 years. He directed the at sea observer program that collected the data on longline boats that were the basis for this study.

Aurauz and Spotila argue for the need to establish well-enforced marine protected areas where both turtles and fish are safe from longlines. They also recommend targeted seasonal closures to longline fishing in coastal waters close to the main turtle nesting beaches when and where sea turtle interactions with the fishery are highest.

They further recommend a general seasonal longline fishery closure for 5 months, from June to November, which can shift, according to the seasonal abundance of mahi mahi.

To enforce these recommendations and provide needed data to manage the fishery, they recommend placing observers on at least half of longline boats, as was done in Chile. Education of local artisanal fishermen would improve their fishing techniques and encourage them to release sea turtles unharmed.

“There is still time to save both the fishery and the turtles if action is taken soon,” Arauz said.

In pursuit of such action, Pretoma and The Leatherback Trust are providing leadership for a coalition of environmental groups in Costa Rica who have united for a special marine conservation initiative called “Front for Our Oceans” (http://www.salvemosnuestrosmares.com/).

For fish and turtle populations to recover successfully, Spotila, who is also chairman of the board of The Leatherback Trust, said, “the challenge is to collect good data on the fishery, establish protected areas of refuge for the animals and to encourage or force INCOPESCA to enforce the laws that have been already passed by the national legislature. What is being done up until now obviously is not working.”

– See more at: http://drexel.edu/now/archive/2013/October/Costa-Rica-Longline-Fishery-Threatens-Sea-Turtles-Sharks/#sthash.lxhf3KK1.dpuf