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1.
Front Immunol ; 15: 1329820, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38590526

RESUMO

The immune system of Asian elephants (Elephas maximus) is poorly studied, compared to that of livestock, rodents or humans. The innate immune response has become a focus of interest in relation to Elephant endotheliotropic herpesviruses (EEHVs). EEHVs cause a fatal hemorrhagic disease (EEHV-HD) and are a significant threat to captive Asian elephant populations worldwide. Similar to other herpesvirus infections, nearly all animals become infected, but only some develop disease. As progression to EEHV-HD is often acute, a robust innate immune response is crucial to control EEHV infections. This is invariably true of the host in the first instance, but it can also potentially be modulated by intervention strategies. Here, two immunostimulant veterinary medicinal products, authorized for use in domestic species, were tested for their ability to induce innate anti-viral immune responses in Asian elephant blood cells. Sequence data were obtained for a range of previously unidentified Asian elephant immune genes, including C-X-C motif chemokine ligand 10 (CXCL10), interferon stimulated gene 15 (ISG15) and myxovirus GTPase 1 (Mx1), and were employed in the design of species-specific qPCR assays. These assays were subsequently used in analyses to determine fold changes in gene expression over a period of 24 hours. This study demonstrates that both immunostimulant medications are capable of inducing significant innate anti-viral immune responses which suggests that both could be beneficial in controlling EEHV infections in Asian elephants.


Assuntos
Elefantes , Infecções por Herpesviridae , Herpesviridae , Humanos , Animais , Ovinos , Elefantes/genética , DNA Bacteriano , Células Sanguíneas , Imunidade Inata , Plasmídeos , Imunização , Adjuvantes Imunológicos , Expressão Gênica
2.
PLoS One ; 19(4): e0298535, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38598472

RESUMO

Elephants have a unique auditory system that is larger than any other terrestrial mammal. To quantify the impact of larger middle ear (ME) structures, we measured 3D ossicular motion and ME sound transmission in cadaveric temporal bones from both African and Asian elephants in response to air-conducted (AC) tonal pressure stimuli presented in the ear canal (PEC). Results were compared to similar measurements in humans. Velocities of the umbo (VU) and stapes (VST) were measured using a 3D laser Doppler vibrometer in the 7-13,000 Hz frequency range, stapes velocity serving as a measure of energy entering the cochlea-a proxy for hearing sensitivity. Below the elephant ME resonance frequency of about 300 Hz, the magnitude of VU/PEC was an order of magnitude greater than in human, and the magnitude of VST/PEC was 5x greater. Phase of VST/PEC above ME resonance indicated that the group delay in elephant was approximately double that of human, which may be related to the unexpectedly high magnitudes at high frequencies. A boost in sound transmission across the incus long process and stapes near 9 kHz was also observed. We discuss factors that contribute to differences in sound transmission between these two large mammals.


Assuntos
Elefantes , Animais , Humanos , Orelha Média/fisiologia , Som , Estribo/fisiologia , Audição/fisiologia , Vibração
3.
PeerJ ; 12: e16746, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38562998

RESUMO

Identifying suitable habitats and conserving corridors are crucial to the long-term conservation of large and conflict-prone animals. Being a flagship species, survival of Asian elephants is threatened by human-induced mortality and habitat modification. We aimed to assess the habitat suitability and connectivity of the Asian elephant Elephas maximus Linnaeus, 1758 habitat in the state of Odisha in eastern India. We followed the ensemble of spatial prediction models using species presence data and five environmental variables. We used least-cost path and circuit theory approaches to identify the spatial connectivity between core habitats for Asian elephants. The results revealed that normalized difference vegetation index (NDVI; variable importance 42%) and terrain ruggedness (19%) are the most influential variables for predicting habitat suitability of species within the study area. Our habitat suitability map estimated 14.6% of Odisha's geographical area (c. 22,442 km2) as highly suitable and 13.3% (c. 20,464 km2) as moderate highly suitable. We identified 58 potential linkages to maintain the habitat connectivity across study area. Furthermore, we identified pinch points, bottlenecks, and high centrality links between core habitats. Our study offers management implications for long-term landscape conservation for Asian elephants in Odisha and highlights priority zones that can help maintain spatial links between elephant habitats.


Assuntos
Elefantes , Animais , Humanos , Ecossistema , Meio Ambiente , Índia
4.
PeerJ ; 12: e16961, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38426137

RESUMO

Colophospermum mopane (mopane) forms mono-dominant woodlands covering extensive areas of southern Africa. Mopane provides a staple foodstuff for elephants, who hedge woodland by reducing trees to small trees or shrubs, leaving emergent trees which are too large to be pollarded. Emergent trees are important for supporting faunal biodiversity, but they can be killed by ringbarking. This study first examined the influence of elephant density on woodland transformation and the height distribution of canopy volume, and, second, whether canopy volume is maintained, and tall emergent trees too large to be broken can persist, under chronic elephant utilisation. Three regimes of 0.23, 0.59 and 2.75 elephants km-2 differed in vegetation structure and the height structure of trees. Areas under the highest elephant density supported the lowest total canopy volume owing to less canopy for plants >3 m in height, shorter trees, loss of most trees 6-10 m in height, but trees >10 m in height (>45 cm stem diameter) persisted. Under eight years of chronic utilisation by elephants, transformed mopane woodland maintained its plant density and canopy volume. Plant density was greatest for the 0-1 m height class, whereas the 3.1-6 m height class provided the bulk of canopy volume, and the 1.1-3 m height layer contained the most canopy volume. Emergent trees (>10 m in height) suffered a loss of 1.4% per annum as a result of debarking. Canopy dieback of emergent trees increased conspicuously when more than 50% of a stem was debarked, and such trees could be toppled by windthrow before being ringbarked. Thus relict emergent trees will slowly be eliminated but will not be replaced whilst smaller trees are being maintained in a pollarded state. Woodland transformation has not markedly reduced canopy volume available to elephants, but the slow attrition of emergent trees may affect supported biota, especially cavity-dependent vertebrate species, making use of these trees.


Assuntos
Elefantes , Fabaceae , Animais , Árvores , Florestas , Plantas
5.
Curr Biol ; 34(5): R211-R213, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38471453

RESUMO

In most eukaryotes, balanced chromosome segregation at meiosis requires crossovers, but female Bombyx mori lack these structures. Instead, the synaptonemal complex is repurposed to compensate for this absence of crossovers, a remarkable example of exaptation.


Assuntos
Bombyx , Elefantes , Animais , Feminino , Elefantes/genética , Bombyx/genética , Meiose , Complexo Sinaptonêmico , Eucariotos/genética , Segregação de Cromossomos
7.
PLoS One ; 19(3): e0299656, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38498501

RESUMO

Syntax, the combination of meaning-devoid phonemes into meaningful words, which in turn are combined in structurally and semantically complex sentences, is fundamental to the unlimited expressiveness of human languages. Studying the functions of call combinations in non-human species provides insights into the evolution of such syntactic capabilities. Here, we investigated the combination of high amplitude broadband calls with low frequency rumble vocalizations in a highly social species, the African forest elephant Loxodonta cyclotis. Rumbles play an integral role in coordinating social interactions by transmitting socially relevant information, including individual identity. By contrast, broadband calls, such as roars, are thought to function as signals of distress and urgency as they are typically produced in situations of high emotional intensity. Functional changes associated with the combination of these calls remain little understood. We found that call combinations were produced by all age-sex classes but were most prevalent in immature individuals. We found that rumbles used singularly occurred in all five investigated social contexts, whereas single broadband calls were restricted to two resource-related contexts. Call combinations also occurred in all five contexts, suggesting an increase in the functional use of broadband calls when combined with rumbles, analogous to the generativity brought about through syntax in human speech. Moreover, combining calls appeared to lead to functional shifts towards high-stake contexts. Call combinations were more likely in competition contexts compared to single rumbles, and more likely in separation contexts compared to single broadband calls. We suggest that call combination in forest elephants may aide to reduce message ambiguity in high-stake situation by simultaneously communicating distress and individual identity, which may be critical to secure access to resources, reduce the risk of injury and to reunite with or recruit the support of the family group.


Assuntos
Elefantes , Vocalização Animal , Animais , Humanos , Comportamento Social , Florestas , Interação Social
8.
J Zoo Wildl Med ; 55(1): 173-181, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38453500

RESUMO

Detailed knowledge of biological variation can facilitate accurate interpretation of clinical pathology parameters. A recent biological variation study in Asian elephants (Elephas maximus) found that hematology parameters had high individuality, which suggests that population-derived reference intervals may be an insensitive diagnostic tool. In elephant medicine, sensitive hematology-related diagnostics are crucial for clinical decision-making, particularly in elephants at risk for elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD). The objective of this study was to assess biological variation of hematology parameters in African elephants to determine whether population-derived reference intervals are a sensitive diagnostic tool for interpreting results and to provide a useful alternative. Eight healthy African elephants had blood collected under behavioral training every other week for 8 wk. Complete blood cell count (CBC) analysis was performed in duplicate to assess analytical variation. Previous methods were used to determine between-individual variation, within-individual variation, index of individuality, and reference change values (RCV). This study found that most hematology parameters displayed intermediate-to-high individuality, which suggests that alternatives to population-derived reference intervals are necessary to detect pathologic changes. To test the results of our biological variation data, a case of EEHV-HD was retrospectively evaluated. Individual normal values and calculated RCV detected a clinically significant monocytopenia, leukopenia, and thrombocytopenia associated with EEHV2 viremia. However, none of these parameters fell outside a population-derived reference interval. This study highlights the utility of biological variation in clinical decision-making and demonstrates that individual normal values and RCV may be important diagnostic tools for CBC interpretation in African elephants.


Assuntos
Elefantes , Hematologia , Infecções por Herpesviridae , Herpesviridae , Animais , Infecções por Herpesviridae/veterinária , Estudos Retrospectivos
9.
J Zoo Wildl Med ; 55(1): 73-85, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38453490

RESUMO

Firocoxib is a COX-2-selective nonsteroidal anti-inflammatory drug (NSAID) with limited effects on COX-1, which means it likely has fewer side effects than typically associated with other NSAIDs. This study determined possible doses of firocoxib based on single- and multidose pharmacokinetic trials conducted in 10 Asian elephants (Elephas maximus). Initially, two single oral dose trials (0.01 and 0.1 mg/kg) of a commercially available tablet (n = 6) and paste (n = 4) formulation were used to determine a preferred dose. The 0.1 mg/kg dose was further evaluated via IV single dose (n = 3) and oral multidose trials (tablets n = 6; paste n = 4). Serum peak and trough firocoxib concentrations were also evaluated in Asian elephants (n = 4) that had been being treated for a minimum of 90 consecutive days. Key pharmacokinetic parameters for the 0.1 mg/kg single-dose trials included mean peak serum concentrations of 49 ± 3.3 ng/ml for tablets and 62 ± 14.8 ng/ml for paste, area under the curve (AUC) of 1,332 ± 878 h*mg/ml for tablets and 1,455 ± 634 h*mg/ml for paste, and half-life (T1/2) of 34.3 ± 30.3 h for tablets and 19.9 ± 12.8 h for paste. After 8 d of dosing at 0.1 mg/kg every 24 h, pharmacokinetic parameters stabilized to an AUC of 6,341 ± 3,003 h*mg/ml for tablets and 5,613 ± 2,262 for paste, and T1/2 of 84.4 ± 32.2 h for tablets and 62.9 ± 2.3 h for paste. Serum COX inhibition was evaluated in vitro and ex vivo in untreated elephant plasma, where firocoxib demonstrated preferential inhibition of COX-2. No adverse effects from firocoxib administration were identified in this study. Results suggest administering firocoxib to Asian elephants at a dose of 0.1 mg/kg orally, using either tablet or paste formulations, every 24 h.


Assuntos
4-Butirolactona/análogos & derivados , Elefantes , Sulfonas , Animais , Ciclo-Oxigenase 2 , Monitoramento de Medicamentos , Administração Oral , Anti-Inflamatórios não Esteroides , Comprimidos , Área Sob a Curva , Estudos Cross-Over , Meia-Vida
10.
J Zoo Wildl Med ; 55(1): 182-194, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38453501

RESUMO

This study examined the viral shedding kinetics of elephant endotheliotropic herpesvirus (EEHV) in African elephants (Loxodonta africana) compared to viral shedding behavior in Asian elephants (Elephas maximus). Little is known about the transmission dynamics and epidemiology of this disease in African elephants. In light of recent clinical cases and mortalities, this paper aims to identify trends in viral biology. Trunk wash samples were collected from 22 African elephants from four North American zoological institutions that had recently experienced herd viremias or translocations. Processing of these samples included DNA extraction followed by qPCR to quantitate viral DNA load. The results were then compared with available literature that chronicled similar cases in Asian and African elephants. Minimal EEHV shedding was detected in response to varied herd translocations. Increased shedding was recorded in herds in which an elephant experienced an EEHV viremia when compared to baseline shedding. These index infections were followed by subsequent viremias in other elephants, although it is not known if these were recrudescence, transient controlled viremias, and/or primary infections via transmission to other elephants. When compared to historically published data, it was observed that EEHV3 cases in African elephants and EEHV1A cases in Asian elephants had consistently higher levels of viral DNA in the blood than were shed in trunk secretions, a fact that is seemingly inconsistent with such severe cases of disease and the high mortality rates associated with those respective types. The findings produced in this study highlight the need for more routine monitoring of viral shedding in African elephant herds to elucidate possible EEHV transmission and recrudescence factors for ex situ population management.


Assuntos
Elefantes , Infecções por Herpesviridae , Herpesviridae , Animais , Infecções por Herpesviridae/epidemiologia , Infecções por Herpesviridae/veterinária , DNA Viral/genética , Viremia/veterinária , Animais de Zoológico/genética , Herpesviridae/genética , Recidiva
11.
J Zoo Wildl Med ; 55(1): 164-172, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38453499

RESUMO

Elephant endotheliotropic herpesvirus (EEHV) can induce fatal hemorrhagic disease (HD) in African elephants (Loxodonta africana). Once clinical signs develop, progression is rapid, even with aggressive treatment. There is a critical need to develop point-of-care diagnostic tests to aid in identification of EEHV-HD prior to the onset of overt clinical signs. Study objectives were to investigate a novel, point-of-care viscoelastic coagulation monitor (VCM Vet), compare the results to thromboelastography (TEG), and report traditional hemostatic analytes in adult African elephants. Whole blood was collected from seven clinically healthy elephants (four females and three males, 18-47 yr) and analyzed in duplicate via VCM Vet and kaolin-activated TEG 1-3 and 30 min following collection, respectively. Separated plasma was frozen for ancillary coagulation testing. Both analyses generated quantifiable clotting reactions with variables (median [range]) describing clot formation rate (VCM Vet, clot time = 682 s [530-987 s], clot formation time = 244 s [186-744 s], Alpha = 40° [14-47°]; TEG, reaction time = 6.2 min [3.7-11.8 min], kinetic time = 1.3 min [0.9-2.6 min], Alpha = 70° [57-77°]), clot strength (VCM Vet, maximum clot formation = 34 units [20-45 units]; TEG, maximum amplitude = 75 mm [69-80 mm], shear elastic modulus strength = 14.7 Kdynes/s [11.3-19.5 Kdynes/s]), and clot lysis (VCM Vet, lysis index at 30 min = 100% [100-99%], lysis index at 45 min = 98% [95-100%]; TEG, lysis index at 30 min = 0% [0-0.4%], lysis index at 60 min = 1.4% [0-2.6%]) recorded. Additional testing (median [range]) included D-dimer concentration (33 ng/ml [28-94 ng/ml]), prothrombin time (12.4 s [12.2-13.2 s]), activated partial thromboplastin time (17.2 s [14.2-18.8 s]), and fibrinogen concentration (297 [282-383] mg/dL). Tracings generated by VCM Vet and TEG were clinically similar, and there was visual agreement and minimal difference between quantitative variables for duplicate tests. VCM Vet is a promising, user-friendly tool for use in identification and management of coagulopathies in African elephants.


Assuntos
Elefantes , Herpesviridae , Masculino , Feminino , Animais , Tromboelastografia/veterinária , Sistemas Automatizados de Assistência Junto ao Leito , Coagulação Sanguínea , Testes de Coagulação Sanguínea/veterinária
12.
J Zoo Wildl Med ; 55(1): 290-294, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38453514

RESUMO

Multiple species of elephant endotheliotropic herpesvirus (EEHV) have caused fatal hemorrhagic disease in African (Loxodonta africana) and Asian (Elephas maximus) elephants. To date, EEHV7 has been detected only in benign pulmonary and skin nodules and in saliva of African elephants and has not been associated with clinical illness. Low-level viremia due to EEHV7A was detected via qPCR in two subadult African elephants during routine surveillance. Hematologic changes were noted in both elephants, including leukopenia, lymphopenia, monocytopenia, and band heterophilia. Treatment was initiated with famciclovir, antimicrobials, and rectal fluids, and one elephant received plasma transfusions due to a progressive decrease in platelet count. Both elephants remained asymptomatic throughout the viremias, with rapid resolution of hematologic abnormalities. These cases add to the current understanding of the epidemiology of EEHV in African elephants; to the authors' knowledge, they represent the first documentation of clinical disease due to EEHV7 infection in any elephant.


Assuntos
Elefantes , Infecções por Herpesviridae , Herpesviridae , Humanos , Animais , Infecções por Herpesviridae/diagnóstico , Infecções por Herpesviridae/epidemiologia , Infecções por Herpesviridae/veterinária , Famciclovir/uso terapêutico , Antivirais/uso terapêutico , Viremia/veterinária
13.
Proc Natl Acad Sci U S A ; 121(13): e2317878121, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38466877

RESUMO

Can insects weighing mere grams challenge our current understanding of fluid dynamics in urination, jetting fluids like their larger mammalian counterparts? Current fluid urination models, predominantly formulated for mammals, suggest that jetting is confined to animals over 3 kg, owing to viscous and surface tension constraints at microscales. Our findings defy this paradigm by demonstrating that cicadas-weighing just 2 g-possess the capability for jetting fluids through remarkably small orifices. Using dimensional analysis, we introduce a unifying fluid dynamics scaling framework that accommodates a broad range of taxa, from surface-tension-dominated insects to inertia and gravity-reliant mammals. This study not only refines our understanding of fluid excretion across various species but also highlights its potential relevance in diverse fields such as ecology, evolutionary biology, and biofluid dynamics.


Assuntos
Elefantes , Hemípteros , Mamífero Proboscídeo , Animais , Ecologia , Evolução Biológica
14.
Viruses ; 16(2)2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38400043

RESUMO

Elephant endotheliotropic herpesviruses (EEHVs), of which eleven (sub)species are currently distinguished, infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, young elephants, specifically those with low to non-detectable EEHV-specific antibody levels, may develop fatal hemorrhagic disease (EEHV-HD) upon infection. However, animals with high antibody levels against EEHV(1A) gB, an immunodominant antigen recognized by antibodies elicited against multiple (sub)species, may also occasionally succumb to EEHV-HD. To better define which animals are at risk of EEHV-HD, gB and gH/gL ELISAs were developed for each of the Asian elephant EEHV subspecies and assessed using 396 sera from 164 Asian elephants from European zoos. Antibody levels measured against gB of different (sub)species correlated strongly with one another, suggesting high cross-reactivity. Antibody levels against gH/gL of different subspecies were far less correlated and allowed differentiation between these (sub)species. Importantly, while high gB-specific antibody levels were detected in the sera of several EEHV-HD fatalities, all fatalities (n = 23) had low antibody levels against gH/gL of the subspecies causing disease. Overall, our data indicate that (sub)species-specific gH/gL ELISAs can be used to identify animals at risk of EEHV-HD when infected with a particular EEHV (sub)species.


Assuntos
Elefantes , Transtornos Hemorrágicos , Herpes Simples , Infecções por Herpesviridae , Herpesviridae , Animais , Infecções por Herpesviridae/diagnóstico , Infecções por Herpesviridae/veterinária
15.
Proc Biol Sci ; 291(2016): 20231638, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38351797

RESUMO

Fierce international debates rage over whether trophy hunting is socially acceptable, especially when people from the Global North hunt well-known animals in sub-Saharan Africa. We used an online vignette experiment to investigate public perceptions of the acceptability of trophy hunting in sub-Saharan Africa among people who live in urban areas of the USA, UK and South Africa. Acceptability depended on specific attributes of different hunts as well as participants' characteristics. Zebra hunts were more acceptable than elephant hunts, hunts that would provide meat to local people were more acceptable than hunts in which meat would be left for wildlife, and hunts in which revenues would support wildlife conservation were more acceptable than hunts in which revenues would support either economic development or hunting enterprises. Acceptability was generally lower among participants from the UK and those who more strongly identified as an animal protectionist, but higher among participants with more formal education, who more strongly identified as a hunter, or who would more strongly prioritize people over wild animals. Overall, acceptability was higher when hunts would produce tangible benefits for local people, suggesting that members of three urban publics adopt more pragmatic positions than are typically evident in polarized international debates.


Assuntos
Conservação dos Recursos Naturais , Elefantes , Animais , Humanos , Animais Selvagens , Caça , Opinião Pública , Equidae
16.
Behav Brain Sci ; 47: e35, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38311452

RESUMO

Integrative experiments, as described, seem blindly empirical, as if the question of generality of effects could not be understood through controlled one-at-a-time experiments. But current research using such experiments, especially applied research, can resolve issues and make progress through understanding of cause-effect pathways, leaving to engineers the task of translating this understanding into practice.


Assuntos
Elefantes , Perna (Membro) , Animais , Humanos
17.
Forensic Sci Int Genet ; 70: 103027, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38422900

RESUMO

Currently, the global elephant population has significantly declined due to the poaching of elephants for their ivory, and this is the reason why elephants are listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, Thailand allows the legal trade of ivory from registered, domesticated Asian elephants, leading to the smuggling of African elephant ivory, and passing them off as Asian elephant ivory. Therefore, this research aims to develop and validate a portable strip test to discriminate between Asian and African elephants DNA, using Recombinase Polymerase Amplification (RPA) and Lateral Flow Dipstick assay (LFD) according to international standards. The results showed that the strip test can be successfully developed with 100% accuracy (n = 105). This kit is specific to elephants, has a detection limit of 0.125 ng of DNA, and can effectively discriminate a variety of elephant ivory, including raw ivory, ivory products, and aged ivory over 25 years old, which had been damaged by fire, all with 100% accuracy (n = 117). Additionally, the developed strip test is designed to be portable and cost-effective. It does not require expensive laboratory equipment and provides a faster analysis process compared with conventional PCR-based methods. This will expedite the legal process and enforcement of laws related to elephant conservation, reducing the opportunities for illegal activities, and enabling timely prosecution under relevant wildlife conservation laws in Thailand and internationally.


Assuntos
Elefantes , Animais , Elefantes/genética , Conservação dos Recursos Naturais , Comércio , Internacionalidade , DNA/genética
18.
Naturwissenschaften ; 111(1): 5, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38294560

RESUMO

In East African savannas, in the rainy season, an elephant dung bolus is usually transformed into a flat mat of dung residue within a few hours. We extracted the coprophilous beetles of a dung mat from a 1 kg bolus after a one-night exposure and counted 13,699 specimens, most of them aphodiine dung beetles. This is the largest number of dung beetles per kilogram of mammal dung ever counted. Given that an elephant produces an average of 160 kg of feces per day, we extrapolate that one adult elephant provides food for 2.12 million dung beetles on any given day. The elephant population in the Laikipia-Samburu ecosystem in central Kenya, an elephant-rich environment, can sustain, by sheer extrapolation, 14.3 billion dung beetles in an area of 55,000 km2, which translates to ca. 260,000 dung beetles/km2. The decline or extinction of elephants, at least in East African grasslands, may have a massive cascade effect on the populations of coprophagous beetles and the biota dependent on or gaining an advantage from them.


Assuntos
Besouros , Elefantes , Fezes , Animais , Ecossistema
19.
Genes (Basel) ; 15(1)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38255007

RESUMO

Richard Peto's paradox, first described in 1975 from an epidemiological perspective, established an inverse correlation between the probability of developing cancer in multicellular organisms and the number of cells. Larger animals exhibit fewer tumors compared to smaller ones, though exceptions exist. Mice are more susceptible to cancer than humans, while elephants and whales demonstrate significantly lower cancer prevalence rates than humans. How nature and evolution have addressed the issue of cancer in the animal kingdom remains largely unexplored. In the field of medicine, much attention has been devoted to cancer-predisposing genes, as they offer avenues for intervention, including blocking, downregulating, early diagnosis, and targeted treatment. Predisposing genes also tend to manifest clinically earlier and more aggressively, making them easier to identify. However, despite significant strides in modern medicine, the role of protective genes lags behind. Identifying genes with a mild predisposing effect poses a significant challenge. Consequently, comprehending the protective function conferred by genes becomes even more elusive, and their very existence is subject to questioning. While the role of variable expressivity and penetrance defects of the same variant in a family is well-documented for many hereditary cancer syndromes, attempts to delineate the function of protective/modifier alleles have been restricted to a few instances. In this review, we endeavor to elucidate the role of protective genes observed in the animal kingdom, within certain genetic syndromes that appear to act as cancer-resistant/repressor alleles. Additionally, we explore the role of protective alleles in conditions predisposing to cancer. The ultimate goal is to discern why individuals, like Winston Churchill, managed to live up to 91 years of age, despite engaging in minimal physical activity, consuming large quantities of alcohol daily, and not abstaining from smoking.


Assuntos
Elefantes , Medicina , Síndromes Neoplásicas Hereditárias , Humanos , Animais , Camundongos , Elefantes/genética , Alelos , Cetáceos
20.
Science ; 383(6681): 433-438, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38271503

RESUMO

Mutualisms often define ecosystems, but they are susceptible to human activities. Combining experiments, animal tracking, and mortality investigations, we show that the invasive big-headed ant (Pheidole megacephala) makes lions (Panthera leo) less effective at killing their primary prey, plains zebra (Equus quagga). Big-headed ants disrupted the mutualism between native ants (Crematogaster spp.) and the dominant whistling-thorn tree (Vachellia drepanolobium), rendering trees vulnerable to elephant (Loxodonta africana) browsing and resulting in landscapes with higher visibility. Although zebra kills were significantly less likely to occur in higher-visibility, invaded areas, lion numbers did not decline since the onset of the invasion, likely because of prey-switching to African buffalo (Syncerus caffer). We show that by controlling biophysical structure across landscapes, a tiny invader reconfigured predator-prey dynamics among iconic species.


Assuntos
Formigas , Equidae , Cadeia Alimentar , Leões , 60587 , Simbiose , Animais , Formigas/fisiologia , Elefantes , Búfalos
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