scholarly journals Intraspecific and Intracolonial Variation in the Profile of Venom Alkaloids and Cuticular Hydrocarbons of the Fire AntSolenopsis saevissimaSmith (Hymenoptera: Formicidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Eduardo Gonçalves Paterson Fox ◽  
Adriana Pianaro ◽  
Daniel Russ Solis ◽  
Jacques Hubert Charles Delabie ◽  
Bruno Cunha Vairo ◽  
...  

Fire ants are aggressive Neotropical ants that are extensively similar in general biology and morphology, making species identification difficult. Some fire ant species are top-rated pests spreading throughout the world by trade vessels. Many researchers attempted to sort between invasive and native species by using chemical characters, including patterns of venom alkaloids. The present study is the first to report intraspecific variation in some chemical characters, namely, cuticular hydrocarbons and venom alkaloids, within the Brazilian fire ant speciesSolenopsis saevissimaand also reports on within-nest variations among members of different castes. Two different haplotypes (cryptic species) ofS. saevissimawere clearly identified, one presenting a predominant combination of the venom alkaloidscis- andtrans-2-methyl-6-undecylpiperidine with the cuticular hydrocarbons C23, 3-Me-C23, 10-C25 : 1, C25, and 3-Me-C25, and the other a predominant combination ofcis- andtrans-2-methyl-6-tridecenylpiperidine with predominance of 12-C25 : 1, C25, 11-Me-C25, 3-Me-C25, 13-C27 : 1, C27, and 13-Me-C27. Intranest variations revealed that the proportions among these compounds varied sensibly among workers of different sizes, gynes, and males (no alkaloids were detected in the latter). Larva contained vestiges of the same compounds. The recorded chemical profiles are quite different from previous reports withS. saevissimasamples from São Paulo. The finds thus support other recent claims thatS. saevissimaincludes cryptic species; the study, moreover, adds the find that they can occur in the same geographical location.

2012 ◽  
Vol 23 (3) ◽  
pp. 659-664 ◽  
Author(s):  
N. A. Freidenfelds ◽  
T. R. Robbins ◽  
T. Langkilde

Abstract Understanding the mechanisms driving adaptations to survive agonistic interactions, and their function, provides insight into how native species adapt to aggressive invaders, a growing global threat. We staged encounters between native fence lizards (Sceloporus undulatus) and red imported fire ants (Solenopsis invicta) on and off the ant mound (nest) to examine the effectiveness of lizard antipredator behavior through ontogeny while focusing on the impact of lifetime and evolutionary exposure to this invasive threat. We used field-caught and lab-reared lizards from a fire ant–invaded and an uninvaded site. In ∼90% of cases, fire ants found lizards within 12 min in natural lizard habitat. Lizards that performed rapid twitches of their body and/or fled after initial encounter with a fire ant scout reduced their risk of having additional fire ants recruit to the attack. The majority of lizards that had been exposed to fire ants within their lifetime (field-caught lizards from the invaded site) behaviorally responded to attack, whereas relatively few lizards that were naïve to fire ants (all lab-reared lizards and field-caught lizards from the uninvaded site) responded. Because fewer adult lizards responded to fire ants than juveniles, they were recruited to by additional attacking ants significantly more than were juveniles. Our data suggest that the higher percentage of responsive adults within invaded populations is the result of within-lifetime selection acting against unresponsive adults, and/or lifetime exposure to fire ants triggering the retention of this juvenile behavior into adulthood, rather than selection acting on a heritable trait across generations.


2017 ◽  
Vol 108 (5) ◽  
pp. 667-673 ◽  
Author(s):  
L. Hu ◽  
R.R. Balusu ◽  
W.-Q. Zhang ◽  
O.S. Ajayi ◽  
Y.-Y. Lu ◽  
...  

AbstractSome fire ants of the genus Solenopsis have become invasive species in the southern United States displacing native species by competition. Although the displacement pattern seems clear, the mechanisms underlying competitive advantage remain unclear. The ability of ant workers to produce relatively larger amount of alarm pheromone may correspond to relative greater fitness among sympatric fire ant species. Here we report on quantitative intra-specific (i.e. inter-caste) and inter-specific differences of alarm pheromone component, 2-ethyl-3,6-dimethylpyrazine (2E36DMP), for several fire ant species. The alarm pheromone component was extracted by soaking ants in hexane for 48 h and subsequently quantified by gas chromatography-mass spectrometry at single ion monitoring mode. Solenopsis invicta workers had more 2E36DMP than male or female alates by relative weight; individual workers, however, contained significantly less pyrazine. We thus believe that alarm pheromones may serve additional roles in alates. Workers of Solenopsis richteri, S. invicta, and hybrid (S. richteri × S. invicta) had significantly more 2E36DMP than a native fire ant species, Solenopsis geminata. The hybrid fire ant had significantly less 2E36DMP than the two parent species, S. richteri and S. invicta. It seems likely that higher alarm pheromone content may have favored invasion success of exotic fire ants over native species. We discuss the potential role of inter-specific variation in pyrazine content for the relationship between the observed shifts in the spatial distributions of the three exotic fire ant species in southern United States and the displacement of native fire ant species.


2020 ◽  
Vol 49 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Karl A Roeder ◽  
Rebecca M Prather ◽  
Anna W Paraskevopoulos ◽  
Diane V Roeder

Abstract For social organisms, foraging is often a complicated behavior where tasks are divided among numerous individuals. Here, we ask how one species, the red imported fire ant (Solenopsis invicta Buren) (Hymenoptera: Formicidae), collectively manages this behavior. We tested the Diminishing Returns Hypothesis, which posits that for social insects 1) foraging investment levels increase until diminishing gains result in a decelerating slope of return and 2) the level of investment is a function of the size of the collective group. We compared how different metrics of foraging (e.g., number of foragers, mass of foragers, and body size of foragers) are correlated and how these metrics change over time. We then tested the prediction that as fire ant colonies increase in size, both discovery time and the inflection point (i.e., the time point where colonial investment toward resources slows) should decrease while a colony’s maximum foraging mass should increase. In congruence with our predictions, we found that fire ants recruited en masse toward baits, allocating 486 workers and 148 mg of biomass, on average, after 60 min: amounts that were not different 30 min prior. There was incredible variation across colonies with discovery time, the inflection point, and the maximum biomass of foragers all being significantly correlated with colony size. We suggest that biomass is a solid indicator of how social taxa invest their workforce toward resources and hypothesize ways that invasive fire ants are able to leverage their enormous workforce to dominate novel ecosystems by comparing their foraging and colony mass with co-occurring native species.


2010 ◽  
Vol 37 (7) ◽  
pp. 566 ◽  
Author(s):  
Tracy Langkilde ◽  
Nicole A. Freidenfelds

Context Aggressive encounters, including those with venomous species, impose selective pressure on native species. Immediate lethal outcomes of these encounters have been the primary focus of research in this field. However, not all aggressive interactions result in immediate mortality, and indirect consequences of aggressive interactions may be an equally important but under-considered selective force. The red imported fire ant is a globally important venomous invader that imposes novel selective pressure on native communities. Aims We examined indirect effects of fire ant envenomation on native fence lizard growth rates and subsequent survival. Methods Fence lizards are subject to fire ant envenomation in the field when they eat fire ants (they are stung inside the mouth) and through fire ant attack (they are stung on the body). We quantified body sizes of adult lizards from fire ant-invaded and uninvaded sites. We then experimentally exposed hatchling fence lizards to the two modes of fire ant envenomation, and quantified their growth and survival over 1 year. Key results Lizards from fire ant-invaded sites were smaller than those from an uninvaded site, even at similar latitudes. However, in contrast to studies on other native taxa, we found no effect of fire ant venom on growth rates of lizards from naïve or fire ant-invaded populations. Lizards exposed to fire ant venom, through both eating and attack, experienced higher rates of delayed mortality, with 34% of lizards dying 1–11 weeks post-envenomation compared with 12% of lizards in the control treatment. These patterns were true for fire ant naïve populations as well as those exposed to fire ants for ~35 generations. Conclusions These results suggest that the smaller body sizes observed in fence lizards from fire ant-invaded sites are not a consequence of exposure to fire ant venom. However, fence lizards from both sites suffer delayed survival costs of fire ant envenomation. Implications The present study highlights the importance of considering indirect fitness consequences of aggressive encounters if we are to fully understand the ecological and evolutionary consequences of these interactions, and adequately manage and predict the impacts of invasive species.


2020 ◽  
Vol 2020 (10-3) ◽  
pp. 82-92
Author(s):  
Gekkaya Funda

The formation of external policy of any country aims at serving the state’s interests. For this matter, many countries seek their way through this by taking into account the potential prospects available to them. The fundamental subtleties and factors that influence a state’s choices of external policy include geographical location, history, security, culture, trade, political ideology, military might, et cetera. Countries often make external contacts based on some regulations and response to unfolding events. Thus, external policy to an extent pertains to the guiding principles outlined to be pursued through state values, decisions and actions taken by the states themselves and their attempt to develop, manage and control the external relations of national societies. In this regard, the Caucasian region has been an important factor in Turkey’s foreign policy. Since these states emerged in the early 1990s, energy has taken a center stage within the region, while Turkey remains a transit route to the world...


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Eduardo Gonçalves Paterson Fox ◽  
Daniel Russ Solis ◽  
Mônica Lanzoni Rossi ◽  
Jacques Hubert Charles Delabie ◽  
Rodrigo Fernando de Souza ◽  
...  

Although common in Brazil, the biology of the fire antSolenopsis saevissima(Smith) is still poorly studied. Larval descriptions are useful to genus-level ant systematics and sometimes to species-level taxonomy. This study presents a detailed description of juveniles ofS. saevissimafrom Brazil, which were compared with Brazilian specimens ofSolenopsis invictaBuren,Solenopsis geminata(Fabricius), andSolenopsis altipunctataPitts. Different larval instars were separated by diagnostic morphological traits which were confirmed by observing moults. Reproductive larvae could be easily sorted by their distinctive body dimensions and shape. Contrary to previous reports on this species, the larvae ofS. saevissimaproved to be generally identical to those ofS. invicta, while a few specimens resembled those of other close species, such asSolenopsis megergatesTrager. Mature larvae thus presented considerable intraspecific variation in some characters recently proposed to aid fire ant species separation (morphology of head hairs).


Author(s):  
Diane Guevara

As background, breast care centers around the world vary in interior design based on geographical location and the trends of the healthcare design process at the time of construction. However, at the forefront of healthcare interior design is the evidence-based design (EBD) process and the Universal Design (UD) guidelines. The Center for Health Design states that the EBD process differs from the linear design process, in that EBD uses relevant evidence to educate and guide the design decisions. The objective of this study was to support future EBD and UD use in the development of patient areas in breast care center interior design. The methods for this study incorporated an extensive review of the literature, examples of eight breast care centers around the world, observations, an interview, and a staff survey concerning the interior design of a local breast care center. The results revealed that using the EBD process and UD, to develop guidelines for patient areas in breast care centers’ interior design, directors could use guidelines to evaluate existing breast care centers or preconstruction for new breast care centers. This study concluded with design guidelines for patient areas in breast care center interior design. The recommended guidelines targeted the following features: robes (vs. hospital gowns), spa-like atmosphere, monochromatic color scheme, use of wood and stone, private check-in areas, wayfinding, room temperature comfort, seating comfort, seating style choices including bariatric, personal items storage, access to natural light, indirect artificial lighting, living plants, views of nature, flooring comfort, and wheelchair accessibility.


2021 ◽  
Vol 21 (4) ◽  
Author(s):  
Mariele P. Camargo ◽  
Sandra C. Forneck ◽  
Fabrício M. Dutra ◽  
Leonardo B. Ribas ◽  
Almir M. Cunico

Abstract The South America ichthyofauna encompasses the highest diversity of the world, however is highly threatened by anthropogenic actions. The fish fauna of nine low-order streams, tributaries of the Piquiri River and impacted by aquaculture, agriculture and urbanization were sampled in the present study. Samplings were done quarterly from December 2017 to September 2018 at three sites in each stream, using a portable electric fishing device in 50-meter segments. A total of 14,507 individuals were collected, belonging to six orders, 20 families, 46 genera, and 70 species. The highest richness and abundance were found for the orders Characiformes and Siluriformes. In this study, nine species that had not been recorded were found, totaling 163 for the basin. In addition, 14 non-native species were captured. The presented list of species contributes to the existing database of ichthyofauna distribution in Neotropical streams, denoting that it is underestimated in the region, mainly in low-order tributaries. The present study reinforces the importance of inventories and monitoring in environments with high biodiversity and sensitive to anthropogenic actions.


Author(s):  
Elena Frolova

Today the whole world continues to look at the surrounding reality through the prism of the coronavirus. A few months ago, in our relatively prosperous life without quarantine, the world-famous Bloomberg agency compiled another rating of countries according to the health index, on top of which were Spain and Italy. When compiling this rating, the average life expectancy of the population, the level of economic development, geographical location, prevalence of bad habits, the availability of clean drinking water, etc. were taken into account. The combination of these indicators provides data for the formation of a health index, which in Spain amounted to 92.8, and in Italy - 91.6. It is believed that the main factor contributing to the high health index in these countries is the favorable climate and the ability to keep to the Mediterranean diet, which is based on olive oil, seafood and a large amount of fruits and vegetables. However, as the tragic reality shows, countries with the best organization of the healthcare system in the world were not able to withstand the epidemic. What is the situation in the country that is the third of the top three in the ranking compiled by Bloomberg - Iceland? There is neither a favourable climate, nor olive oil, nor fresh shrimps, and the average temperature in the summer months there is +10°C. Nevertheless, in terms of life expectancy, this country left behind all the Scandinavian countries and came close to Singapore and Japan. And if we talk about the prevalence of coronavirus, then as of early April, as a result of testing of 4.7% of the population 1364 cases were found in the country, and the number of deaths was only 4. A mass examination of citizens, notably free of charge for everyone, immediate tracking of the routes of infection and isolation of the ill allowed the Icelandic authorities to take control of the situation from the very beginning of the epidemic, even without the introduction of strict restrictive measures [1].


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