Atlantoscia Floridana Research Articles

Two new records of terrestrial isopods (Isopoda, Oniscidea) from the state of Paraíba, Brazil

Two species of Oniscidea are recorded for the state of Paraíba for the first time. Cubaris murina Brandt, 1833 from Campina Grande and Cabaceiras and Porcellionides pruinosus (Brandt, 1833) from Campina Grande. Moreover, Alloniscus buckupi Campos-Filho & Cardoso, 2018 and Atlantoscia floridana (Van Name, 1940) have their distribution extended, and a short discussion about the record of A. buckupi in a semiarid area is provided.

How coexistence may influence life history: the reproductive strategies of sympatric congeneric terrestrial isopods (Crustacea, Oniscidea)

Patterns of allocation between reproduction, survival, and maintenance are what we call life history. By investigating the life-history strategy of sympatric species, we may understand how they are able to coexist, as different strategies are expected to evolve in species that occupy similar niche space. Terrestrial isopods are a group in which multiple species frequently inhabit the same area. Notably, they are usually infected by Wolbachia Hertig, 1936, a notorious manipulator of the hosts’ reproductive processes. Thus, the aim of this study was to analyze the investment in reproduction in three sympatric and closely related species of terrestrial isopods: Atlantoscia floridana (Van Name, 1940), Atlantoscia inflata Campos-Filho and Araujo, 2015, and Atlantoscia petronioi Campos-Filho, Contreira and Lopes-Leitzke, 2012, only the latter being infected with Wolbachia. We showed that the presence of the bacteria seems not to affect the fitness of A. petronioi, because there was no clear difference in the reproductive output of infected and noninfected individuals. On the other hand, we observed that the three species possess alternative life-history strategies; that is, they differ in how much they invest in maintenance (body size) and reproductive effort. Such differences probably facilitate the species coexistence, reducing the competition among them.

Morphology, microhabitat selection and life-history traits of two sympatric woodlice (Crustacea: Isopoda: Oniscidea): A comparative analysis

The soil is a heterogeneous habitat with layers that differ in many aspects. Soil animals’ morphological adaptations relate to specific microhabitat. We compared cuticle surface structures and ultrastructure of Balloniscus glaber (endogeic) and Atlantoscia floridana (epigeic) using microscopy techniques to understand how morphological characteristics allow sympatry. Species differed in scale and sensillum type and disposition, as well as cuticle thickness and layer proportion. Balloniscus glaber has curved scales and robust, caudally oriented sensilla that are most likely adaptive features for endogeic lifestyle. Its cuticle has high overall thickness and numerous stacks that provide toughness compatible with clinging strategy and higher tolerance to seasonal fluctuation. Atlantoscia floridana is an epigeic species with flat scales and long perpendicular sensilla, not adapted to the soil layer. Its delicate and flexible cuticle with thinner stacks makes it an agile runner although with lower tolerance to seasonal changes. Overall, differences in surface structure are related to microhabitat selection and ecological niche, so species can occur in same location. Differences in cuticle ultrastructure relate to behavioral strategies and environmental tolerance. This way, knowledge of species’ ecology is complemented by morphological data that can help to explain habitat partition.

Diversity and population characteristics of terrestrial isopods (Crustacea, Oniscidea) across three forest environments in southern Brazil

Terrestrial isopods are important and dominant component of meso and macrodecomposer soil communities. The present study investigates the diversity and species composition of terrestrial isopods on three forests on the Serra Geral of the state of Rio Grande do Sul, Brazil. The area has two natural formations (Primary Woodland and Secondary Woodland) and one plantation of introduced Pinus. The pitfall traps operated from March 2001 to May 2002, with two summer periods and one winter. There were 14 sampling dates overall. Of the five species found: Alboscia silveirensis Araujo, 1999, Atlantoscia floridana (van Name, 1940), Benthana araucariana Araujo & Lopes, 2003 (Philoscidae), Balloniscus glaber Araujo & Zardo, 1995 (Balloniscidae) and Styloniscus otakensis (Chilton, 1901) (Styloniscidae); only A. floridana is abundant on all environments and B. glaber is nearly exclusive for the native forests. The obtained data made it possible to infer about population characteristics of this species. The Similarity Analysis showed a quantitative difference among the Secondary forest and Pinus plantation, but not a qualitative one. The operational sex ratio (OSR) analysis for A. floridana does not reveal significant differences in male and female proportions among environments. The reproductive period identified in the present study for A. floridana was from spring to autumn in the primary forest and Pinus plantation and during all year for the secondary forest. The OSR analysis for B. glaber reveals no significant differences in abundance between males and females for secondary forest, but the primary forest was a significant difference. The reproductive period for B. glaber extended from summer to autumn (for primary and secondary forest). This is the first record for Brazil of an established terrestrial isopod population in a Pinus sp. plantation area, evidenced by the presence of young, adults and ovigerous females, balanced sex ratio, expected fecundity and reproduction pattern, as compared to populations from native vegetation areas.

VARIAÇÃO SAZONAL E ESTRUTURA POPULACIONAL DE ESPÉCIES DE ISÓPODOS TERRESTRES EM UMA ÁREA EM SUCESSÃO VEGETAL

This study aimed to analyze the seasonal variation and population structure of terrestrial isopods species in a successional environment. During the study period were identified five species of isopods collected in 6623 individuals. Atlantoscia floridana 1 Biologo, graduado em Ciencias Biologicas pela Universidade de Santa Cruz do Sul – UNISC; 2 Professor do Departamento de Biologia e Farmacia, Universidade de Santa Cruz do Sul – UNISC; 3 Avenida Independencia, 2293, Bairro Universitario CEP 96815-900 Santa Cruz do Sul, RS – Brasil. Caderno de Pesquisa, serie Biologia, volume 24, numero 3 45 and Balloniscus sellowii were the two most frequent species, accounting for 99,7% of the total sample. Differences in the reproductive cycle were found for both species. A. floridana species proved to be more general for the environment studied, presenting continuous reproductive cycle. Analysis by operational sex-ratio (OSR) showed greater mobilization of males during the months of low temperatures and increased humidity (April, May and June). In B. sellowii isopod species of lower mobility, there was an interruption of the reproductive cycle in the months of lowest temperature. The lowest record of OSR was observed from the month of May, returning higher values for the months of November, February and March, indicating a greater mobilization of the species in the summer months. As with other work already done to the south of Brazil, some similar patterns of seasonality were identified, however, the presence of low OSR for the two dominant species may be indicative of influence of plant succession.

Detection of Wolbachia (Alphaproteobacteria: rickettsiales) in three species of terrestrial isopods (crustacea: isopoda: oniscidea) in Brazil

Terrestrial isopods are widely infected with Wolbachia. However, little is known about the presence of bacteria in the Neotropical species. The objective of this study was to test the hypothesis of presence of Wolbachia infection in the native species of terrestrial isopods, Atlantoscia floridana and Circoniscus bezzii, and in the introduced species Burmoniscus meeusei.

Neotropical woodlice (isopoda) colonizing leaf-litter of pioneer plants in a coal residue disposal environment

The irregular disposal of coal combustion residues has adverse impacts on terrestrial ecosystems. Pioneer plants and soil invertebrates play an important role in the recovery of these areas. The goal of this study was to investigate the colonization patterns of terrestrial isopods (Oniscidea) in leaf litter of three spontaneous pioneer plants (grass - Poaceae, shrub - Euphorbiaceae, tree - Anarcadiaceae) at sites used for fly ash or boiler slag disposal. The experiment consisted of eight blocks (four per disposal site) of 12 litter bags each (four per plant species) that were randomly removed after 6, 35, 70 or 140 days of field exposure. Three isopod species were found in the litter bags: Atlantoscia floridana (van Name, 1940) (Philosciidae; n = 116), Benthana taeniata Araujo & Buckup, 1994 (Philosciidae; n = 817) and Balloniscus sellowii (Brandt, 1833) (Balloniscidae; n = 48). The isopods colonized the three leaf-litter species equally during the exposure period. However, the pattern of leaf-litter colonization by these species suggests a conflict of objectives between high quality food and shelter availability. The occurrence of A. floridana and the abundance and fecundity of B. taeniata were influenced by the residue type, indicating that the isopods have different degrees of tolerance to the characteristics of the studied sites. Considering that terrestrial isopods are abundant detritivores and stimulate the humus-forming processes, it is suggested that they could have an indirect influence on the soil restoration of this area.

OS ISÓPODOS TERRESTRES SÃO BOAS FERRAMENTAS PARA MONITORAR E RESTAURAR ÁREAS IMPACTADAS POR METAIS PESADOS NO BRASIL?

Restoration Ecology aims at the restoration of degraded environments and seeks an integrated management of its resources. It has been considered as a long-term solution, not only to reconstitute the original landscape, but also to give back functionality to these enviromnments. Using tools as phytoremediation, Restoration Ecology aims to decrease or eliminate the negative effects of contaminants in polluted areas. To be effective, restoration projects need both short-term and long-term biomonitoring, and for that matter the knowledge on bioindicator organisms is required. Terrestrial isopods are macroinvertebrate detritivores that can bioaccumulate large quantities of heavy metals. They have been long used as models in the terrestrial ecotoxicology and therefore have a great potential to be employed as biomonitors during the phytoremediation of polluted lands. In Brazil, knowledge on the species' biology, ecology and distribution is still very incipient, nonetheless it is possible to identify two species with potential to be used as biomonitors. Atlantoscia floridana (Philosciidae) and Balloniscus sellowii (Balloniscidae) are Neotropical species with large geographical distribution in Brazil and show an enhanced capacity to colonize degraded lands. In the future, with a better knowledge on these species' physiology, the combination of phytoremediation and terrestrial isopods as biomonitors may enhance the ecological restoration of lands contaminated by heavy metals.

Life history comparison of two terrestrial isopods in relation to habitat specialization

For many animal species, there is a relationship between life history strategies, as predicted by the r– K-selection theory, degree of habitat specialization and response to habitat alteration and loss. Here we compare two sympatric woodlice species with contrasting patterns of habitat use and geographical distribution. We predict that Atlantoscia floridana (Philosciidae), considered a habitat generalist, would exhibit the r-selected traits, whereas Balloniscus glaber (Balloniscidae), considered a habitat specialist, should have the K-selected traits. We analyzed several life history traits as well as life and fecundity tables using 715 and 842 females of A. floridana and B. glaber, respectively, from populations living in syntopy in southern Brazil. As predicted, most evaluated traits allow A. floridana to be considered an r-strategist and B. glaber a K-strategist: A. floridana showed a shorter lifetime, faster development, earlier reproduction, a smaller parental investment, higher net reproductive rate ( R 0), a higher growth rate ( r) and a shorter generation time ( T) in comparison to B. glaber. A. floridana seems to be a successful colonizer with a high reproductive output. These characteristics explain its local abundance, commonness and wide geographical distribution. On the contrary, B. glaber has a restricted geographical distribution that is mainly associated with Atlantic forest fragments, a biome threatened by deforestation and replacement by monocultures. Its narrow distribution combined with the K-selected traits may confer to this species an increased extinction risk.

An assemblage of terrestrial isopods (Crustacea) in southern Brazil and its contribution to leaf litter processing

We present an assemblage of terrestrial isopods in Parque Estadual de Itapuã, southern Brazil, and estimate the contribution of two species to the leaf litter processing. After one year of sampling, we obtained 3748 individuals of six species and four eco-morphologic groups (in order of abundance): Balloniscus glaber Araujo & Zardo, 1995, Atlantoscia floridana (van Name, 1940), Pseudodiploexochus tabularis (Giambiagi de Calabrese, 1939), Trichorhina sp., Alboscia itapuensis Araujo & Quadros, 2005 and Novamundoniscus gracilis Lopes & Araujo, 2003. Total monthly density corresponded to 368 individuals per square meter. The species A. itapuensis and N. gracilis represented less than 1% of total individuals. All the others showed aggregated distribution. Atlantoscia floridana and B. glaber had the highest proportion of individuals occurring together (88%) and a significant species association. Their monthly biomass averaged 4.92 kg ha-1 for B. glaber and 0.97 kg ha-1 for A. floridana. Consumption rates, obtained in the lab (in mg mg-1 day-1) were 0.34 ± 0.04 and 0.70 ± 0.18 for B. glaber and A. floridana, respectively and assimilation efficiency was about 30%. We estimated that both species together could process 860 kg leaves ha-1 year-1.

Terrestrial isopod diversity in the subtropical neotropics: Itapuã State Park, southern Brazil

We analysed species abundance and composition during one year of sampling at Itapuã State Park, a conservation unit in the State of Rio Grande do Sul, southern Brazil. Samples were collected monthly from May 2003 to April 2004 along a 4 km forest trail divided in three transects along the slopes of a small hill. Terrestrial isopods were hand searched by three people for 40 minutes at two sampling sites along each transect, summing 240 minutes of sampling effort per transect per month. Six species distributed in six families were found. The collector curve stabilised when half the samples were taken, demonstrating sampling sufficiency: analytical estimates did not predict more species to be found in the trail. Atlantoscia floridana (van Name, 1940) was dominant in all transects. Abundance varied along the year with a summer and a winter peak, but peaks were not consistent among transects. The first part of the trail, used for ecotourism, was less diverse, had less species (4 as compared to 6 in the other transects), and was thus also less similar in composition.

Population structure and reproductive biology of Atlantoscia floridana (van Name, 1940) (Crustacea, Isopoda, Oniscidea) in southern Brazil

Abstract Data were obtained on the population structure and reproduction of Atlantoscia floridana, one of the most common species of terrestrial isopods in the restinga (coastal dune) forests of the state of Rio Grande do Sul, southern Brazil. During a 19-month period, a total of 7833 individuals were sampled: 2792 males, 3400 females and 1691 mancas. There was a significant difference between the size of both males and females collected in 2000 and 2001: the mean size was smaller in the second year when individuals in the larger size classes were lacking. Population density varied with season. The minimum population was 131 ind per m2 individuals, the maximum 1040 ind per m2 and the mean 450 per m2. While the overall sex ratio was clearly female biased, the operational sex ratio favored males, and showed no changes with season. Because both ovigerous and post-ovigerous females were present throughout the year, reproduction is considered continuous; however, reproduction peaked during autumn and spring. Ovigerous females were measured (CW = cephalothorax width) and the number of eggs was counted. Fecundity (F) varied from 5 to 23 eggs ( x ¯ = 11.18 ± 4) per female, and was expressed by the regression F = –18.48 + 22.59 CW, with the female cephalothorax width varying from 1.04 to 1.68 mm. Marsupial mortality was only 0.9%. Egg production was 588 eggs per m2 in spring and 660 eggs per m2 in autumn. Recruitment occurred in all months, and eggs, embryos and marsupial mancas were also present year-round. A. floridana is the dominant species of terrestrial isopod in the study area. Its most remarkable characteristic is its high reproductive investment.

Postmarsupial development of Atlantoscia floridana (van Name, 1940) (Crustacea, Isopoda, Oniscidea): sexual differentiation and size at onset of sexual maturity

Summary The postmarsupial development of Atlantoscia floridana (van Name, 1940) was studied, with emphasis on the sexual differentiation and maturity. Samples were obtained in the Reserva Biológica do Lami, Porto Alegre, RS, Brazil, during 2000 and 2002. Collected animals were reared in the laboratory under temperatures of about 20±1°C and observed daily. Animals preserved in 70% ethanol were used to analyze sexual maturity. Growth was monitored as each animal moulted for evidence of sexual differentiation. The development of the male genitalia and the female genital pore was described across the different juvenile stages. Female sexual maturity was estimated to occur at a minimum size of 1.04 mm cephalothorax width. Male sexual maturity was estimated from the morphometric relationship between cephalothorax width and length of the genital papilla and indicated the puberal moult to occur at a minimum size of 0.77 mm cephalothorax width. Identification of the size at which sexual maturity occurs allows recognizing the postmarsupial juvenile stages of both males and females: JUI to JU III for males and JU I to JU VI for females. Males reach sexual maturity in approximately 1.5 months after leaving the marsupium, and females in about 3 months.

Postmarsupial development of Atlantoscia floridana (van Name, 1940) (Crustacea, Isopoda, Oniscidea): the manca stages

In this paper we describe the postmarsupial development of the manca stages of Atlantoscia floridana (van Name, 1940). Ovigerous females were collected in Reserva Biológica do Lami, Porto Alegre, RS, Brazil and separately reared in small containers at 20°C (±1°C). After birth each newborn (manca I) was reared separately in order to observe the subsequent moults. In a period of about 12 h the animals underwent the first moult. The manca II stage lasts 9.16±1.57 days while manca III takes up a period of 9.96±1.05 days. Growth was observed through measurements of cephalothorax width. The three manca stages are described, illustrated and compared with the adults. The main distinguishing characteristics among mancas I, II and III are presented as well as the b/c and d/c co-ordinates of the noduli laterales.

Growth curve of Atlantoscia floridana (van Name) (Crustacea, Isopoda, Philosciidae) from a Brazilian Restinga Forest

The terrestrial isopod Atlantoscia floridana (van Name, 1940) occurs from the U.S.A. (Florida) to Brazil and Argentina. In the southernmost Brazilian State, Rio Grande do Sul, the species is recorded in many localities, in urban and in non-urban areas. The growth curve of Atlantoscia floridana based on field data is presented. The specimens were sampled from April, 2000 to October, 2001 at the Reserva Biológica do Lami (RBL), Rio Grande do Sul. Captured individuals were sexed and had their cephalothorax width measured, with the data analyzed with von Bertalanffy's model. The growth curves for males and females are described, respectively, by the equations: Wt = 1.303 [1 - e-0.00941 (t + 50.37)] and Wt = 1.682 [1 - e-0.00575 (t + 59.13)]. The curves showed differential growth between sexes, where females reach a higher Wµ with a slower growth rate. Based on the growth curves it was also possible to estimate life expectancy for males and females.

First report of pigmentation dystrophy in terrestrial isopods, Atlantoscia floridana (van Name) (Isopoda, Oniscidea), induced by larval acanthocephalans

The observation of pigmentation alteration in isopod crustaceans induced by acanthocephalans, known as pigmentation dystrophy, has been documented in North America in species of the aquatic genera Asellus Geoffroy, 1764, Lirceus Rafinesque-Schmaltz, 1820, and Caecidotea Packard, 1871, and in Europe, in Asellus. Recently, three depigmented specimens of Atlantoscia floridana (van Name, 1940), a terrestrial isopod, occurring from >Florida, USA to northern Argentina were found showing pigmentation dystrophy and harboring larval acanthocephalans. Photographic documentation of live and preserved, infected isopods is presented. Morphometric data and photomicrographs of the male, unencysted cystacanth specimen which allowed its placement in the genus Centrorhynchus Luhe, 1911 are presented. This is the first record of the phenomenon of pigmentation dystrophy in terrestrial isopod crustaceans, the first record of A. floridana infected by an acanthocephalan and the first record of a species of Centrorhynchus in a terrestrial isopod.