Southern Elephant Seal Research Articles

Metabolic heat loss in southern elephant seals (Mirounga leonina) differs with stage of moult and between habitats.

The moult in southern elephant seals (Mirounga leonina) represents an especially energetically demanding period during which seals must maintain high skin temperature to facilitate complete replacement of body fur and upper dermis. In this study, heat flux from the body surface was measured on 18 moulting southern elephant seals to estimate metabolic heat loss in three different habitats (beach, wallow and vegetation). Temperature data loggers were also deployed on 10 southern elephant seals to monitor skin surface temperature. On average, heat loss of animals on the beach was greater than in wallows or vegetation, and greater in wallows than in vegetation. Heat loss across all habitats during the moult equated to 1.8 x resting metabolic rate (RMR). The greatest heat loss of animals was recorded in the beach habitat during the late moult, that represented 2.3 x RMR. Mass loss was 3.6±0.3kg day-1, resulting in changes in body condition as the moult progressed. As body condition declined, skin surface temperature also decreased, suggesting that as animals approached the end of the moult blood flow to the skin surface was no longer required for hair growth.

Elephant seals (Mirounga leonina) at Potter Peninsula, King George Island, Antarctica: genetic variation of the breeding colony and gene flow with other colonies

Elephant seals (Mirounga leonina) at Potter Peninsula, King George Island, Antarctica: genetic variation of the breeding colony and gene flow with other colonies

Elephant seal foraging success is enhanced in Antarctic coastal polynyas.

Antarctic polynyas are persistent open water areas which enable early and large seasonal phytoplankton blooms. This high primary productivity, boosted by iron supply from coastal glaciers, attracts organisms from all trophic levels to form a rich and diverse community. How the ecological benefit of polynya productivity is translated to the highest trophic levels remains poorly resolved. We studied 119 southern elephant seals feeding over the Antarctic shelf and demonstrated that: (i) 96% of seals foraging here used polynyas, with individuals spending on average 62% of their time there; (ii) the seals exhibited more area-restricted search behaviour when in polynyas; and (iii) these seals gained more energy (indicated by increased buoyancy from greater fat stores) when inside polynyas. This higher-quality foraging existed even when ice was not present in the study area, indicating that these are important and predictable foraging grounds year-round. Despite these energetic advantages from using polynyas, not all the seals used them extensively. Factors other than food supply may influence an individual's choice in their use of feeding grounds, such as exposure to predation or the probability of being able to return to distant sub-Antarctic breeding sites.

Body volume and mass estimation of southern elephant seals using 3D range scanning and neural network models

AbstractDirect measures of body mass of marine mammals are logistically complicated to obtain even for pinnipeds. An alternative method for mass estimation based on 3D imaging technology and automated processing algorithms, was tested in southern elephant seals (Mirounga leonina). Two models of artificial neural networks (ANN)—nonlinear neural network and self‐organizing maps—were trained to compute the volume and to estimate the mass of the digital models, previously obtained by scanning individuals with an infrared light sensor. Body mass estimates were as accurate (mean % error = 4.4) as estimates in previous photogrammetry studies in southern elephant seals and the mass predictive ability of the trained ANN was higher (99% of the variance explained) than other predictive models using photogrammetry in pinniped studies. While this method has proven to produce accurate body mass estimates, it also overcame some of the constraints of other indirect techniques, avoiding animal disturbance caused by physical restraint or chemical immobilization, minimizing risks, and capitalizing on the time working in the field. The results of these estimations were promising, which shows that the proposed methodology can provide adequate results with lower logistic and computational requirements.

Sex, body size, and boldness shape the seasonal foraging habitat selection in southern elephant seals.

Selecting foraging habitat is a fundamental behavior in the life of organisms as it directly links resource acquisition to fitness. Differences in habitat selection among individuals may arise from several intrinsic and extrinsic factors, and yet, their interaction has been given little attention in the study of wild populations. We combine sex, body size, and boldness to explain individual differences in the seasonal foraging habitat selection of southern elephant seals (Mirounga leonina) from the Kerguelen Archipelago. We hypothesize that habitat selection is linked to the trade‐off between resource acquisition and risk, and that individuals differ in their position along this trade‐off because of differences in reproductive strategies, life stages, and metabolic requirements. Before the post‐molt foraging trip, we used a novel object approach test to quantify the boldness of 28 subadult and adult females and 42 subadult males and equipped them with data loggers to track their movements at sea. Subadult males selected neritic and oceanic habitats, whereas females mostly selected less productive oceanic habitats. Both sexes showed a seasonal shift from Antarctic habitats in the south in the summer to the free of ice subantarctic and subtropical habitats in the north in the winter. Males avoided oceanic habitats and selected more productive neritic and Antarctic habitats with body size mostly in the winter. Bolder males selected northern warmer waters in winter, while shyer ones selected the Kerguelen plateau and southern colder oceanic waters. Bolder females selected the Kerguelen plateau in the summer when prey profitability is assumed to be the highest. This study not only provides new insights into the spatiotemporal foraging ecology of elephant seals in relation to personality but also emphasizes the relevance of combining several intrinsic and extrinsic factors in understanding among‐individual variation in space use essential in wildlife management and conservation.

Front Cover

The cover image relates to the Research Article https://doi.org/10.1111/ddi.13447 “Habitat model forecasts suggest potential redistribution of marine predators in the southern Indian Ocean” by Reisinger et al. An adult male southern elephant seal (Mirounga leonina) at Marion Island, southern Indian Ocean. Image credit: Ryan Reisinger.

Seasonal Transformation and Spatial Variability of Water Masses Within MacKenzie Polynya, Prydz Bay

AbstractWe provide a detailed description of the spatial distribution, seasonality and transformation of the main water masses within MacKenzie Polynya (MP) in Prydz Bay, East Antarctica, using data from instrumented southern elephant seals. Dense Shelf Water (DSW) formation in MP shows large spatial variability that is related to the (a) local bathymetry, (b) water column preconditioning from the presence/absence of different water masses, and (c) proximity to the Amery Ice Shelf meltwater outflow. MP exhibits sustained sea ice production and brine rejection (thus, salinity increase) from April to October. However, new DSW is only formed from June onward, when the mixed layer deepens and convection is strong enough to break the stratification set by Antarctic Surface Water above and Ice Shelf Water below. We found no evidence of DSW export from MP to Darnley polynya, as previously suggested. Rather, our observations suggest some DSW formed in Darnley Polynya may drain toward the western Prydz Bay. Then, DSW is exported offshore from Prydz Bay through the Prydz Channel. The interplay between sea ice formation, meltwater input, and sea floor topography is likely to explain why some coastal polynyas form more DSW than others, as well as the temporal variability in DSW formation within a particular polynya.

Where are the beachmasters? Unexpectedly weak polygyny among southern elephant seals on a South Shetland Island

AbstractIntraspecific variation in animal mating systems can have important implications for ecological, evolutionary and demographic processes in wild populations. For example, patterns of mating can impact social structure, dispersal, effective population size and inbreeding. However, few species have been studied in sufficient detail to elucidate mating system plasticity and its dependence on ecological and demographic factors. Southern elephant seals (Mirounga leonina) have long been regarded as a textbook example of a polygynous mating system, with dominant ‘beachmaster’ males controlling harems of up to several hundred females. However, behavioural and genetic studies have uncovered appreciable geographic variation in the strength of polygyny among elephant seal populations. We, therefore, used molecular parentage analysis to investigate patterns of parentage in a small satellite colony of elephant seals at the South Shetland Islands. We hypothesised that dominant males would be able to successfully monopolise the relatively small numbers of females present in the colony, leading to relatively high levels of polygyny. A total of 424 individuals (comprising 33 adult males, 101 adult females and 290 pups) sampled over 8 years were genotyped at 20 microsatellites and reproductive success was analysed by genetically assigning parents. Paternity could only be assigned to 31 pups (10.7%), despite our panel of genetic markers being highly informative and the genotyping error rate being very low. The strength of inferred polygyny was weak in comparison to previous genetic studies of the same species, with the most successful male fathering only seven pups over the entire course of our study. Our results show that, even in a species long regarded as a model for extreme polygyny, male reproductive skew can vary substantially among populations.

A novel animal-borne miniature echosounder to observe the distribution and migration patterns of intermediate trophic levels in the Southern Ocean

Despite expanding in-situ observations of marine ecosystems by new-generation sensors, information about intermediate trophic levels remains sparse. Indeed, mid-trophic levels, while encompassing a broad range of zooplankton and micronekton organisms that represent a key component of marine ecosystems and sustain large and diverse communities of marine predators, are challenging to sample and identify. In this study, we examined whether an animal-borne miniature active echosounder can provide information on the distribution and movements of mid-trophic level organisms. If so, such a sonar tag, harnessing the persistent diving behaviour of far-ranging marine mammals, could greatly increase the density of data on this under-studied biome. High-frequency (1.5 MHz) sonar tags were deployed simultaneously with oceanographic tags on two southern elephant seals (Mirounga leonina), at the Kerguelen Islands and Valdés Peninsula (Argentina), and recorded acoustic backscatter while the seals foraged respectively in the Indian and the Atlantic sectors of the Southern Ocean. The backscatter varied widely over time and space, and the seals attempted to capture only a small fraction of the insonified targets. Diel vertical migration patterns were clearly identifiable in the data, reinforcing our confidence in the ability of the sonar tags to detect living mid-trophic organisms along with possibly sinking biological detritus. Moreover, CTD tags attached to the same animals indicated how the abundance, size distribution, and diel migration behaviour of acoustic targets varied with water bodies. These preliminary results demonstrate the potential for animal-borne sonars to provide detailed in-situ information. Further validation effort will make it a valuable tool to refine the estimation of carbon export fluxes as well as for assessing the variation of mid-trophic level biomass according to oceanographic domains and seasons.

Physical changes recorded by a deep diving seal on the Patagonian slope drive large ecological changes

The Patagonian slope is the region where Subantarctic waters and bathymetry give raise to physical and ecological processes that support a rich biodiversity and a large-scale industrial fisheries. Unique among the species that depend on this region is the deep diving southern elephant seal, Mirounga leonina. We report here on changes in the foraging behavior of a female seal explained by the combined effect of a cold and high salinity water mass and a decrease in surface chlorophyll-a concentration. Behavioral and oceanographic data from about 5000 profiles of temperature, conductivity, pressure, light and prey encounters were collected within an area ranging 59.5–61°W and 46–47.5°S, at depths of 300–700 m, on the Patagonian slope, during November–December 2018. A decrease in temperature (0.15 °C) and an increase in salinity (0.03) was found below the mixed layer, during December. Light data revealed a significant increase of irradiance in December (almost reaching the ocean bottom) associated with a decrease of chlorophyll-a in the upper levels. Concomitantly, the seal had a different diving behavior in December, foraging near the surface at night and close to the bottom during daylight hours. Also, the seal doubled the prey capture attempts in December compared to November. This study reveals the importance of ocean physical properties on seal's diving and foraging behavior, and how this changes, although small, can impact on seals diet and body composition during their post-breeding trips.

Mercury and stable carbon and nitrogen isotopes in the natal Fur of two Antarctic pinniped species

Southern elephant seal (SES) and Antarctic fur seal (AFS) are short Southern Ocean food web top predators and are spatial and temporal trend bioindicators of Antarctic Hg bioavailability. Hg, stable isotope composition (δ13C and δ15N) and trophic position (TP) regarding sex were determined using lanugo samples from Antarctic pinnipeds pups (SES n = 35 and AFS n = 11). Hg concentrations in over 50% of the SES pups (mean 5.9 ± 3.1 mg kg−1 dry wt.) are compatible with those found to cause neurologic damage to polar bears in the Arctic. No significant differences regarding sexes for SES or AFS are found based on mean Hg concentrations normalized by body weight. δ15N values and TPs are similar among both species, indicating that gestating SES and AFS mothers feed at the same trophic level. Significantly different δ13C values were found, indicating distinct feeding grounds for mothers belonging to both species when pup lanugo is formed in utero; while SES females like to feed in Antarctic waters, AFS females remain in sub-Antarctic waters. The differences in Hg and δ13C observed for both species reflect not only contrasting feeding habits and anthropogenic Hg inputs, but also maternal foraging strategies.

Climate influences on female survival in a declining population of southern elephant seals (Mirounga leonina).

The Southern Ocean has been disproportionately affected by climate change and is therefore an ideal place to study the influence of changing environmental conditions on ecosystems. Changes in the demography of predator populations are indicators of broader shifts in food web structure, but long‐term data are required to study these effects. Southern elephant seals (Mirounga leonina) from Macquarie Island have consistently decreased in population size while all other major populations across the Southern Ocean have recently stabilized or are increasing. Two long‐term mark‐recapture studies (1956–1967 and 1993–2009) have monitored this population, which provides an opportunity to investigate demographic performance over a range of climatic conditions. Using a 9‐state matrix population model, we estimated climate influences on female survival by incorporating two major climatic indices into our model: The Southern Annular Mode (SAM) and the Southern Oscillation Index (SOI). Our best model included a 1 year lagged effect of SAM and an unlagged SOI as covariates. A positive relationship with SAM1 (lagged) related the previous year's SAM with juvenile survival, potentially due to changes in local prey availability surrounding Macquarie Island. The unlagged SOI had a negative effect on both juvenile and adult seals, indicating that sea ice dynamics and access to foraging grounds on the East Antarctic continental shelf could explain the different contributions of ENSO events on the survival of females in this population.

I've got you under my skin: inflammatory response to elephant seal's lice.

Seals (Phocidae) undergo an annual cycle of moulting that implies hair regeneration, and in the case of southern elephant seals, it also involves the superficial strata of the epidermis. Therefore, surviving the moulting period is crucial for their obligate and permanent ectoparasites. Throughout evolutionary time, sucking lice (Echinophtiriidae) have developed morphological, behavioural and ecological adaptations to cope with the amphibious lifestyle of their hosts. Lepidophthirus macrorhini, the Southern elephant seal louse species, faces the additional challenge of surviving attached to the host during the moulting period. Since lice live on the skin, L. macrorhini has developed a unique survival strategy by piercing the skin of their host, thus keeping them protected from moulting. During fieldwork in Patagonia and Antarctica, skin samples with lice within were collected for histological analysis to assess whether these parasites caused damage to the host. Lice generate an inflammatory process in the host's dermis, and these lesions could alter the normal chemical and mechanical protective properties of the skin facilitating secondary infections. Further studies that analyse the potential pathogens in those skin lesions are necessary to properly assess the real impact of ectoparasites on their host health.

The status of the fur seal population (Arctocephalus gazelle) on the southern border of the distribution area (the Argentine Islands archipelago)

The study of the population status of Arctocephalus gazella (Peters, 1875) in waters of the Argentine Islands was carried out in the period from April 2015 to March 2016 in accordance with the objectives of the State Target Scientific and Technical Research Program of Ukraine in Antarctica for 2011–2020. The aim of the article is to study the population dynamics and distribution of the southern fur seal in waters of the Argentine Islands. Due to the lack of data on the specifics of the seal’s dispersal in different periods of the year and the dynamics of the species population at the southern border of the distribution range, the results of the research are relevant and of great importance. In the second half of the 20th century, some publications presented the results of monitoring of pinnipeds at the Argentine Islands and adjacent territories, but the objects of these studies usually were other seal species: Hydrurga leptonyx, Lobodon carcinophagus, Leptonychotes weddelli, and Mirounga leonina. In the early 21st century, monitoring of the fauna of the Argentine Islands was carried out by Ukrainian biologists. However, they focused on Leptonychotes weddelli and less on other species of pinnipeds. The field material was collected in waters of the Argentine Islands, which is located in the Pacific sector of Antarctica. The fur seal population census and distribution studies were conducted according to the generally accepted methods. After breeding season on the subantarctic islands, during the migration southwards, fur seals reach the Argentine Islands, usually in the third decade of January. In the summer of 2016, the first fur seal was recorded within the archipelago on 31 January. During the study period, the largest number of animals within the archipelago was recorded in March–April and it ranged from 300 to 400 individuals. On the islands of the archipelago, the main resting places of seals were identified. The movement of animals northwards starts in May, consequently a decrease in the number of animals in this region is observed at that time. The last individuals are recorded in the first half of August. In 2015, migration began in May and ended in early August. There are several periods that were characterized by intensive migration of the animals: late June, 5–8 July, and 29 July to 6 August. In winter, one individual was last found within the archipelago on 12 August. The migration is launched by the worsening of weather conditions, formation of a continuous ice cover, reduced availability of food, and other factors.

Determinants of moult haulout phenology and duration in southern elephant seals

Phenological shifts are among the most obvious biological responses to environmental change, yet documented responses for Southern Ocean marine mammals are extremely rare. Marine mammals can respond to environmental changes through phenological flexibility of their life-history events such as breeding and moulting. Southern elephant seals (Mirounga leonina) undergo an obligatory annual moult which involves the rapid shedding of epidermal skin and hair while seals fast ashore. We quantified the timing (phenology) and duration (the time from arrival ashore to departure) of the moult haulout of 4612 female elephant seals at Marion Island over 32 years. Using linear mixed-effects models, we investigated age, breeding state and environmental drivers of moult timing and haulout duration. We found no clear evidence for a temporal shift in moult phenology or its duration. Annual variation in moult arrival date and haulout duration was small relative to age and breeding effects, which explained more than 90% of the variance in moult arrival date and 25% in moult haulout duration. All environmental covariates we tested explained minimal variation in the data. Female elephant seals moulted progressively later as juveniles, but adults age 4 and older had similar moult start dates that depended on the breeding state of the female. In contrast, moult haulout duration was not constant with age among adults, but instead became shorter with increasing age. Moulting is energetically expensive and differences in the moult haulout duration are possibly due to individual variation in body mass and associated metabolizable energy reserves, although other drivers (e.g. hormones) may also be present. Individual-based data on moult arrival dates and haulout duration can be used as auxiliary data in demographic modelling and may be useful proxies of other important biological parameters such as body condition and breeding history.

An engineering perspective on the development and evolution of implantable cardiac monitors in free-living animals.

The latest technologies associated with implantable physiological monitoring devices can record multiple channels of data (including: heart rates and rhythms, activity, temperature, impedance and posture), and coupled with powerful software applications, have provided novel insights into the physiology of animals in the wild. This perspective details past challenges and lessons learned from the uses and developments of implanted biologgers designed for human clinical application in our research on free-ranging American black bears (Ursus americanus). In addition, we reference other research by colleagues and collaborators who have leveraged these devices in their work, including: brown bears (Ursus arctos), grey wolves (Canis lupus), moose (Alces alces), maned wolves (Chrysocyon brachyurus) and southern elephant seals (Mirounga leonina). We also discuss the potentials for applications of such devices across a range of other species. To date, the devices described have been used in fifteen different wild species, with publications pending in many instances. We have focused our physiological research on the analyses of heart rates and rhythms and thus special attention will be paid to this topic. We then discuss some major expected step changes such as improvements in sensing algorithms, data storage, and the incorporation of next-generation short-range wireless telemetry. The latter provides new avenues for data transfer, and when combined with cloud-based computing, it not only provides means for big data storage but also the ability to readily leverage high-performance computing platforms using artificial intelligence and machine learning algorithms. These advances will dramatically increase both data quantity and quality and will facilitate the development of automated recognition of extreme physiological events or key behaviours of interest in a broad array of environments, thus further aiding wildlife monitoring and management.This article is part of the theme issue ‘Measuring physiology in free-living animals (Part I)’.

Developing UAV Monitoring of South Georgia and the South Sandwich Islands’ Iconic Land-Based Marine Predators

Many remote islands present barriers to effective wildlife monitoring in terms of challenging terrain and frequency of visits. The sub-Antarctic islands of South Georgia and the South Sandwich Islands are home to globally significant populations of seabirds and marine mammals. South Georgia hosts the largest breeding populations of Antarctic fur seals, southern elephant seals and king penguins as well as significant populations of wandering, black-browed and grey-headed albatross. The island also holds important populations of macaroni and gentoo penguins. The South Sandwich Islands host the world’s largest colony of chinstrap penguins in addition to major populations of Adélie and macaroni penguins. A marine protected area was created around these islands in 2012 but monitoring populations of marine predators remains a challenge, particularly as these species breed over large areas in remote and often inaccessible locations. During the 2019/20 austral summer, we trialled the use of an unoccupied aerial vehicle (UAV; drone) to monitor populations of seals, penguins and albatross and here we report our initial findings, including considerations about the advantages and limitations of the methodology. Three extensive southern elephant seal breeding sites were surveyed with complete counts made around the peak pupping date, two of these sites were last surveyed 24 years ago. A total of nine islands, historically recorded as breeding sites for wandering albatross, were surveyed with 144 fledglings and 48 adults identified from the aerial imagery. The UAV was effective at surveying populations of penguins that nest on flat, open terrain, such as Adélie and chinstrap penguin colonies at the South Sandwich Islands, and an extensive king penguin colony on South Georgia, but proved ineffective for monitoring macaroni penguins nesting in tussock habitat on South Georgia as individuals were obscured or hidden by vegetation. Overall, we show that UAV surveys can allow regular and accurate monitoring of these important wildlife populations.

Positive early-late life-history trait correlations in elephant seals.

Correlations between early- and late-life performance are a major prediction of life-history theory. Negative early-late correlations can emerge because biological processes are optimized for early but not late life (e.g., rapid development may accelerate the onset of senescence; "developmental theory of aging") or because allocation to early-life performance comes at a cost in terms of late-life performance (as in the disposable soma theory). But variation in genetic and environmental challenges that each individual has to cope with during early life may also lead to positive early-late life-history trait correlations (the "fixed heterogeneity" or "individual quality" hypothesis). We analyzed individual life-history trajectories of 7,420 known-age female southern elephant seals (Mirounga leonina) monitored over 36yr to determine how actuarial senescence (a proxy for late-life performance) correlate with age at first reproduction (a proxy for early-life performance). As some breeding events may not be detected in this field study, we used a custom "multievent" hierarchical model to estimate the age at first reproduction and correlate it to other life-history traits. The probability of first reproduction was 0.34 at age 3, with most females breeding for the first time at age 4, and comparatively few at older ages. Females with an early age of first reproduction outperformed delayed breeders in all aspects we considered (survival, rate of senescence, net reproductive output) but one: early breeders appeared to have an onset of actuarial senescence 1 yr earlier compared to late breeders. Genetics and environmental conditions during early life likely explain the positive correlation between early- and late-life performance. Our results provide the first evidence of actuarial senescence in female southern elephant seals.

Status of pinnipeds on mid-Atlantic ridge islands, South Atlantic Ocean

The status of pinnipeds on mid-Atlantic ridge islands is reviewed to detect trends that may relate to climate change. Small numbers of southern elephant seals Mirounga leonina breed on Gough Island (40°S, 10°W) and at Bouvetoya (54°24′S, 03°21′E) where numbers remained small over ~ 68 years. Vagrant southern elephant seals wandered farther north to tropical Saint Helena Island (15°57′S, 5°41′W) in historical times but have not been recorded there more recently. This suggests a contraction of their distributional range, as manifested in the decline in numbers to imminent extinction at Gough Island. At Gough Island and at Tristan da Cunha (37°05′S, 12°17′W), leopard seals Hydrurga leptonyx and Antarctic fur seals Arctocephalus gazella are occasional seasonal transients from Antarctic and sub-Antarctic islands and the circumpolar sea ice farther to the south. Large populations of Antarctic fur seals A. gazella and sub-Antarctic fur seals A. tropicalis breed at Bouvetoya and Gough Island, respectively. The current state of both populations is uncertain as other populations of conspecifics in the South Atlantic and South Indian oceans are in decline ostensibly contingent upon reduced food availability, likely precipitated by climate change.

A Tale of 20 Alphaviruses; Inter-species Diversity and Conserved Interactions Between Viral Non-structural Protein 3 and Stress Granule Proteins.

Alphaviruses infect a diverse range of host organisms including mosquitoes, mammals, and birds. The enigmatic alphavirus non-structural protein 3 (nsP3) has an intrinsically disordered, C-terminal hypervariable domain (HVD) that can interact with a variety of host proteins associated with stress granules (SGs). The HVD displays the highest variability across the more than 30 known alphaviruses, yet it also contains several motifs that are conserved amongst different subgroups of alphaviruses. For some alphaviruses, specific nsP3–SG protein interactions are essential for virus replication. However, it remains difficult to attribute general roles to these virus-host interactions, as multiple amino acid motifs in the HDV display a degree of redundancy and previous studies were performed with a limited number of alphaviruses. To better understand nsP3-host protein interactions we conducted comprehensive co-localization experiments with the nsP3s of 20 diverse alphaviruses: chikungunya, Semliki Forest, Sindbis, Bebaru, Barmah Forest, Getah, Mayaro, Middelburg, O'nyong-nyong, Ross River QML and T48, Una, Whataroa, Southern Elephant Seal, Eilat, Tai Forest (TAFV), Venezuelan/Eastern/Western equine encephalitis (V/E/WEEV) and the aquatic Salmonid alphavirus (SAV), with three different SG proteins (G3BP and its insect homolog Rasputin, FMRP) and BIN1 in mammalian and mosquito cell lines. Despite that all terrestrial alphavirus nsP3s contained at least one BIN1-binding motif (PxPxPR), not all nsP3s co-localized with BIN1. Further, all alphaviruses except SAV, TAFV and VEEV displayed co-localization with G3BP. Although viruses lacking FGxF-like motifs contained Agenet-like domain binding motifs to facilitate interaction with FMRP, cytoplasmic nsP3 granules of all tested alphaviruses co-localized with FMRP. Crispr-Cas9 knockout of G3BP in mammalian cells abolished nsP3-FMRP co-localization for all alphaviruses except V/E/WEEV nsP3s that bind FMRP directly. G3BP knockout also changed nsP3 subcellular localization of Bebaru, Barmah Forest, Getah, and Sindbis viruses. Taken together this study paints a more detailed picture of the diverse interactions between alphavirus nsP3 and SG-associated host proteins. The interaction between nsP3 and G3BP clearly plays a central role and results in recruitment of additional host proteins such as FMRP. However, direct binding of FMRP can make the interaction with G3BP redundant which exemplifies the alternate evolutionary paths of alphavirus subgroups.