RESUMO
Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.
Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.
RESUMO
Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects' tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.
Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.
Assuntos
Animais , Artrópodes , Poluentes Químicos da Água/toxicidade , Hemípteros , Herbicidas/toxicidade , Ecotoxicologia , GenitáliaRESUMO
Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects' tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.
Assuntos
Artrópodes , Hemípteros , Herbicidas , Poluentes Químicos da Água , Animais , Ecotoxicologia , Genitália , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
Euglossini (Hymenoptera: Apidae, Apini), also known as orchid bees, are endemic to the Neotropical region (Nemésio and Rasmussem, 2011). They are well-known and widely distributed taxon in the Atlantic Forest with more than 60 species (included in four distinct genera) registered in this biome (Nemésio, 2009; Garraffoni et al., 2017). The Atlantic Rain Forest originally occupied about 15% of the Brazilian territory, but it was completely fragmented in forest remnants, and now covers 11-16% of its original area (Ribeiro et al., 2009; Joly et al., 2014). Our knowledge about orchid bee diversity in urban forest fragments is very scarce (Nemésio and Silveira, 2007; Cordeiro et al., 2013), although diverse communities of wild bees have been surprisingly found in cities around the world (Nemésio and Silveira, 2007; Burr et al., 2016). Thus, our aim in this study was a rapid assessment of the orchid bee fauna in the vicinity of an Atlantic Forest remain. The strategy of intensive sampling over a few days in the rainy season are common and has been demonstrated to be very useful to know the orchid bee fauna of an area (Nemésio, 2013a, b). Data were collected in an urban area (22º4940S-47º0610W; altitude 630 m), among fruit and ornamental trees, distant 200 m of the east edge of an Atlantic Forest remnant called Santa Genebra Forest (Campinas, SP), the second larger urban forest in Brazil (252 ha). It is a semideciduous forest and the regional climate is the Cfa of Köppen (humid subtropical with a hot summer). Orchid bee males were collected at a fixed site using seven bait traps as described in Viotti et al. (2013), and bottles of 0.5 L. Each trap received one of the seven baits: 1,8-cineole, eugenol, vanillin, β-ionone, benzyl acetate, methyl trans-cinnamate, and methyl salicylate; and were randomly hanged in shaded branches at about 1.5 m above the ground and distant at least 2 m from each other. The collections were done during five consecutive days (from day 6th to 10th) in February of both 2015 and 2016, from 9:00 to 17:00 h (when the bees are most active). The scents were replaced every day, and cineole three times a day. Captured bees were pinned, identified and deposited at Coleção de Abelhas da Universidade Federal dos Vales do Jequitinhonha e Mucuri. Taxonomic decisions were based on Moure's Bee Catalogue (Moure et al., 2012). Species accumulation curves were constructed for the data set from each sampling year separately or for both years jointly. Sampling efficiency was also evaluated by nonparametric richness estimators (Chao 1, Chao 2, Jackknife 1, Jackknife 2, and Bootstrap) available in the EstimateS 9.1.0 software (Colwell, 2006).(AU)