Fertilization in an egg-brooding colonial ascidian does not vary with population density

The possibility that free-spawning marine organisms may be subject to fertilization failure at low population density (due to the effects of sperm dilution) has sparked much interest, but these effects have been demonstrated only in a few species that broadcast their eggs. Some egg-brooding species may overcome dilution effects by filtering low concentrations of sperm from seawater and fertilizing eggs throughout an extended period of time. We examined the effects of population density and size on fertilization in Botryllus schlosseri, a hermaphroditic colonial ascidian that free-spawns sperm, but broods eggs. We experimentally manipulated the size and density of mating groups and surveyed fertilization levels in natural populations that varied in density. Fertilization was not affected by variation in population size or density in either the experimental or natural populations. Near the end of the reproductive season, some eggs may have been fertilized too late to complete development, suggesting a temporal form of sperm limitation that has not been considered in other systems. We also detected greater variability in fertilization levels at lower population density. Nevertheless, these results suggest that caution must be used in extrapolating reported density effects on fertilization to all taxa of free-spawners; density effects may be reduced in brooders that have efficient sperm collection mechanisms.     

Reproductive assurance varies with flower size in Collinsia parviflora (Scrophulariaceae)

A central question in plant evolutionary ecology is how mixed mating systems are maintained in the face of selection against self-pollination. Recently, attention has focused on the potential reproductive assurance (RA) benefit of selfing: the ability to produce seeds via autonomous selfing when the potential for outcrossing is reduced or absent. To date, there is little experimental support for this benefit under natural pollination conditions. In addition, the RA hypothesis has not been tested experimentally in a species displaying morphological variation for traits expected to influence the mating system, such as flower size, which affects both attractiveness to pollinators and ability to self autonomously. Here, we document significant among-population variation in flower size in Collinsia parviflora and show that pollinators preferred large flowers over small flowers in experimental arrays. The pollinator community varied among three study sites, and two small-flowered populations had lower pollinator visitation rates than one large-flowered population. We compared seed production between intact flowers (can self) and experimentally emasculated flowers (require a pollinator) on large- and small-flowered plants. As predicted by the RA hypothesis, small-flowered plants show a greater RA benefit of selfing than large-flowered plants; emasculated, small flowers produced very few seeds, relative to intact, small flowers or either emasculated or intact, large flowers. We also show that the RA benefit is pollination-context dependent, differing between small- and large-flowered test sites, likely due to a combination of pollinator discrimination against small flowers and differences between test sites in the pollinator community. This paper is the first experimental evidence showing a trait-dependent RA benefit of selfing under natural pollination conditions.     

Widespread seed limitation affects plant density but not population trajectory in the invasive plant Centaurea solstitialis

In some plant populations, the availability of seeds strongly regulates recruitment. However, a scarcity of germination microsites, granivory or density-dependent mortality can reduce the number of plants that germinate or survive to flower. The relative strengths of these controls are unknown for most plant populations and for exotic invaders in particular. We conducted a seed addition experiment with a granivore exclusion treatment in a field setting to explore how these factors interact to regulate populations of the widespread invader Centaurea solstitialis (yellow starthistle) at three study sites across the plant’s range in California. We coupled the experimental approach with observational studies within established C. solstitialis populations to estimate seed rain, recruitment and mortality at natural densities. Seed limitation occurred in both experimental and observational plots in all populations. Although vertebrate granivores were active at each site, they had no effect on C. solstitialis recruitment. Density increased mortality, but the effect was variable and weak relative to its effect on fecundity. The seed limitation that was evident at the seedling stage persisted to flowering. Seed-limited populations such as these ought to be highly sensitive to losses to seed predators, and many biological control agents, including those established for C. solstitialis, are seed predators. However, flowering plant density was decoupled from seed production by a strong compensatory response in the surviving plants; seed production was nearly constant in plots across all seed addition levels. Thus, flowering plant density is reduced by the established biocontrol agents, but seed production compensates to replace the population every generation, and no long-term decline is predicted.     

Male parentage does not vary with colony kin structure in a multiple-queen ant

Kin selection theory predicts that, in social Hymenoptera, the parentage of males should be determined by within-colony relatedness. We present a model showing that, when sex ratios are split (bimodal) as a function of colony kin structure, the predictions of kin selection theory regarding the occurrence of worker reproduction and policing (prevention of worker reproduction) require modification. To test the predictions of kin selection theory and our model, we estimated using microsatellites the frequency of worker-produced male eggs and adults in the facultatively polygynous (multiple-queen) ant Leptothorax acervorum. Analysis of 210 male eggs and 328 adult males from 13 monogynous (single-queen) and nine polygynous colonies demonstrated that the frequency of worker-produced males was low (2.3-4.6% of all males) and did not differ significantly between colony classes or between eggs and adults. This suggested workers' self-restraint as the cause of infrequent worker reproduction in both colony classes. Such an outcome is not predicted either by comparing relatedness values or by our model. Therefore, it appears that factors other than colony kin structure and sex ratio effects determine the pattern of male parentage in the study population. A likely factor is a colony-level cost of worker reproduction.     

Vigilance does not covary with group size in an island population of silvereyes (Zosterops lateralis)

Numerous studies on different taxonomic groups have found thatvigilance behavior is negatively correlated with group size,as predicted by several theoretical models. This follows thelogical argument that each individual in a larger group canspend less time scanning for predators (and more time feeding),while the group as a whole maintains a high probability of detectingan approaching predator. We investigated the relationship betweenthese variables in the population of silvereyes (Zosterops lateralischlorocephala) on Heron Island, Great Barrier Reef. The studyused procedures of field observation that controlled or measuredother variables with which vigilance is often correlated: fooddensity and quality, temperature, time of day, distance fromcover, habitat obstructions, observer proximity, breeding status,age, sex, and dominance. There was no relationship between scanningbehavior and group size under these conditions. There are severalpossible explanations, related to the silvereyes' biology, forthis lack of covariation. An additional explanation is thatHeron Island is a predator-free environment for this species,and covariation between group size and vigilance is not expectedin the absence of predators.     

When bigger is not better: intraspecific competition for pollination increases with population size in invasive milkweeds

One of the essential requirements for an introduced plant species to become invasive is an ability to reproduce outside the native range, particularly when initial populations are small. If a reproductive Allee effect is operating, plants in small populations will have reduced reproductive success relative to plants in larger populations. Alternatively, if plants in small populations experience less competition for pollination than those in large populations, they may actually have higher levels of reproductive success than plants in large populations. To resolve this uncertainty, we investigated how the per capita fecundity of plants was affected by population size in three invasive milkweed species. Field surveys of seed production in natural populations of different sizes but similar densities were conducted for three pollinator-dependent invasive species, namely Asclepias curassavica, Gomphocarpus fruticosus and G. physocarpus. Additionally, supplemental hand-pollinations were performed in small and large populations in order to determine whether reproductive output was limited by pollinator activity in these populations. Reproductive Allee effects were not detected in any of the study species. Instead, plants in small populations exhibited remarkably high levels of reproductive output compared to those in large populations. Increased fruit production following supplemental hand-pollinations suggested that the lower reproductive output of naturally pollinated plants in large populations is a consequence of pollen limitation rather than limitation due to abiotic resources. This is consistent with increased intraspecific competition for pollination amongst plants in large populations. It is likely that the invasion of these milkweed species in Australia has been enhanced because plants in small founding populations experience less intraspecific competition for pollinators than those in large populations, and thus have the ability to produce copious amounts of seeds.     

Small population size limits reproduction in an invasive grass through both demography and genetics

Small populations of founding individuals or survivors of incomplete management programs often represent critical transitions in biological invasions. Theory predicts that population size affects reproduction and, consequently, a population’s expansion, but there are few empirical tests, and fewer that account for the reduced genetic diversity that often accompanies small population size. We created experimental small populations of invasive ryegrass (Lolium multiflorum) with population size varying independently from genetic diversity. Treatment independence was achieved by cloning plants to increase population size without changing diversity. Plant fitness was measured as the proportion of florets producing a seed. We analyzed the effects of population size, genetic diversity, and their interaction using ANCOVAs, one of which accounted for variation in individual plant growth. As predicted, smaller populations produced significantly lower proportion seed set. Low genetic diversity also reduced seed set, but this was best interpreted as part of a significant interaction with population size. Specifically, the effect of population size on the proportion seed set was over five times larger for populations in the medium genetic diversity treatment than the highest diversity treatment, and 6.7 times larger for populations with the lowest level of diversity. Population size variation had biologically meaningful consequences, as the rate of seed set within the low diversity treatment increased by 80 % with increasing population size. The results indicate that both the demographics and genetics of populations can influence reproduction and invasive potential, and must be considered when assessing risk and designing management plans for invasive plants.     

Flowering phenology of invasive alien plant species compared with native species in three Mediterranean-type ecosystems

Background and Aims

Flowering phenology is a potentially important component of success of alien species, since elevated fecundity may enhance invasiveness. The flowering patterns of invasive alien plant species and related natives were studied in three regions with Mediterranean-type climate: California, Spain and South Africa''s Cape region.

Methods

A total of 227 invasive–native pairs were compared for seven character types across the regions, with each pair selected on the basis that they shared the same habitat type within a region, had a common growth form and pollination type, and belonged to the same family or genus.

Key Results

Invasive alien plant species have different patterns of flowering phenology from native species in the three regions. Whether the alien species flower earlier, later or at the same time as natives depends on the climatic regime in the native range of the aliens and the proportion of species in the invasive floras originating from different regions. Species invading at least two of the regions displayed the same flowering pattern, showing that flowering phenology is a conservative trait. Invasive species with native ranges in temperate climates flower earlier than natives, those from Mediterranean-type climates at the same time, and species from tropical climates flower later. In California, where the proportion of invaders from the Mediterranean Basin is high, the flowering pattern did not differ between invasive and native species, whereas in Spain the high proportion of tropical species results in a later flowering than natives, and in the Cape region early flowering than natives was the result of a high proportion of temperate invaders.

Conclusions

Observed patterns are due to the human-induced sympatry of species with different evolutionary histories whose flowering phenology evolved under different climatic regimes. The severity of the main abiotic filters imposed by the invaded regions (e.g. summer drought) has not been strong enough (yet) to shift the flowering pattern of invasive species to correspond with that of native relatives. It does, however, determine the length of the flowering season and the type of habitat invaded by summer-flowering aliens. Results suggest different implications for impacts at evolutionary time scales among the three regions.Key words: Biological invasions, flowering phenology, genetic inertia, Cape Floristic Region, California, Spain, Mediterranean-type ecosystems, water availability, climatic origin     

Schooling preferences for familiar fish vary with group size in a wild guppy population

The ability of fish to recognize and preferentially associate with familiar conspecifics has been well documented in a series of laboratory experiments. In this paper we investigate the schooling preferences of wild female guppies, Poecilia reticulata, in the Upper Tunapuna River in Trinidad and confirm that they do indeed prefer to associate with familiar individuals. The guppies in this river occur in a series of pools that become isolated during the dry season. These fish interact solely with other individuals in their pool for periods of several months at a time and thus have ample opportunity to become accustomed to one another. Our study also reveals that the tendency of female guppies to school with familiar fish declines as the group size in which they naturally live increases. Preferences are strong when there are small numbers of females in a pool, but diminish thereafter. This indicates that the expression of familiarity is constrained by group size. The basis of recognition and the consequences of schooling preferences for familiar individuals are discussed.     

Effective population size associated with self-fertilization: lessons from temporal changes in allele frequencies in the selfing annual Medicago truncatula

Despite its significance in evolutionary and conservation biology, few estimates of effective population size (N(e)) are available in plant species. Self-fertilization is expected to affect N(e), through both its effect on homozygosity and population dynamics. Here, we estimated N(e) using temporal variation in allele frequencies for two contrasted populations of the selfing annual Medicago truncatula: a large and continuous population and a subdivided population. Estimated N(e) values were around 5-10% of the population census size suggesting that other factors than selfing must contribute to variation in allele frequencies. Further comparisons between monolocus allelic variation and changes in the multilocus genotypic composition of the populations show that the local dynamics of inbred lines can play an important role in the fluctuations of allele frequencies. Finally, comparing N(e) estimates and levels of genetic variation suggest that H(e) is a poor estimator of the contemporaneous variance effective population size.     

Effects of vegetation cutting on the invasive plant Coreopsis lanceolata vary with vegetation type

The invasive plant Coreopsis lanceolata has established itself among various native vegetation types in Japan, but comparative studies of control effects among multiple vegetation types invaded by this plant are few. In the present study, experiments involving vegetation cutting at different frequencies were carried out on three vegetation types: Zoysia japonica dominant type (Zj), C. lanceolata dominant type (Cl) and Miscanthus sinensis dominant type (Ms). Responses of C. lanceolata to changes in cutting frequency varied with vegetation type. In Zj, the abundance of C. lanceolata increased when cutting was performed once or not at all, but tended to decrease when it was performed twice or thrice. In Cl, cutting once increased C. lanceolata, but this species was reduced when other cutting frequencies were employed. In Ms, C. lanceolata increased linearly with cutting frequency. The number of inflorescences of C. lanceolata in the plots was negatively correlated with cutting frequency in Zj and Cl. In Ms, the flowering of C. lanceolata was sometimes observed when cutting was performed only once. The most effective way to suppress C. lanceolata was not necessarily the best way to recover the natives. In Zj, cutting once positively influenced the abundances of native herbs, while cutting thrice or not at all tended to decrease them. In Cl and Ms, cutting thrice reduced the abundances of native herbs, while other cutting frequencies tended to increase them. To control invasive plants and restore the invaded vegetation effectively, the management approach should be changed flexibly in response to vegetation type, and careful monitoring of both invasive and native plants is desirable.     

Body protein does not vary despite seasonal changes in fat in the White Stork Ciconia ciconia

To understand how a large soaring bird, the White Stork Ciconia ciconia , copes with energy constraints, we compared changes in body mass in 14 captive adult storks with the body composition of 12 free-ranging adult storks found dead from accidents. The captive storks, already in an enclosure for several years, were fed ad libitum . They were weighed daily for 1.53.5 years using an automatic device. The bodies of the accidentally killed storks were analysed to determine total water, lipid, protein and ash contents, and to assess the biochemical composition of certain organs. Females were on average 20% lighter and 24% smaller than males, but the body mass of the sexes varied in parallel throughout the year. Body mass peaked in December and January (2530% above minimal body mass), due essentially to large fat stores in subcutaneous and abdominal adipose tissues. Body mass and body lipid rapidly decreased from February to June, whether the storks reared chicks successfully or not, and remained minimal for a few days into July. In contrast to birds using flapping flight, no variation in body protein or pectoral muscle protein was observed while breeding, even though the moult occurred then, nor in August, before the time when wild storks migrate. An endogenous regulation of body fuels is discussed.     

Primase p49 mRNA expression is serum stimulated but does not vary with the cell cycle.

Expression of the small-subunit p49 mRNA of primase, the enzyme that synthesizes oligoribonucleotides for initiation of DNA replication, was examined in mouse cells stimulated to proliferate by serum and in growing cells. The level of p49 mRNA increased approximately 10-fold after serum stimulation and preceded synthesis of DNA and histone H3 mRNA by several hours. Expression of p49 mRNA was not sensitive to inhibition by low concentrations of cycloheximide, which suggested that the increase in mRNA occurred before the restriction point control for cell cycle progression described for mammalian cells and was not under its control. p49 mRNA levels were not coupled to DNA synthesis, as observed for the replication-dependent histone genes, since hydroxyurea or aphidicolin had no effect on p49 mRNA levels when added before or during S phase. These inhibitors did have an effect, however, on the stability of p49 mRNA and increased the half-life from 3.5 h to about 20 h, which suggested an interdependence of p49 mRNA degradation and DNA synthesis. When growing cells were examined after separation by centrifugal elutriation, little difference was detected for p49 mRNA levels in different phases of the cell cycle. This was also observed when elutriated G1 cells were allowed to continue growth and then were blocked in M phase with colcemid. Only a small decrease in p49 mRNA occurred, whereas H3 mRNA rapidly decreased, when cells entered G2/M. These results indicate that the level of primase p49 mRNA is not cell cycle regulated but is present constitutively in proliferating cells.     

Reproductive success of Dactylorhiza incarnata ssp. incarnata (Orchidaceae): the effects of population size and plant visibility

Reproduction of plants pollinated solely by flower-visiting animals depends on the ability of the population and each of its flowering member to attract pollinators. Factors affecting the pollination of nectarless species differ somewhat from those affecting the pollination of rewarding species due to the avoidance behaviour of pollinators after visiting empty flowers.
We studied a non-mimic food-deceptive orchid, Dactylorhiza incarnata ssp. incarnata, in 16 populations in central Finland to examine if population properties and plant size affected reproductive success of plants.
We found that the number of flowering plants increased total pollinia removal and seed production of the population, but had no effect on reproduction of individual plants. Dactylorhiza incarnata occurred in open mires with virtually no rewarding species in the neighbourhood, but the distance from the forest edge did not have any effect on reproduction. However, increased variation in the number of flowers among within-population plants enhanced plant reproductive success. The increased variation probably hampered the learning process of flower visitors. Plant size affected reproductive success only in populations with a high general reproductive success indicating that in the rarely visited populations, pollination of individual plants is mainly affected by random effects.     

Shoot herbivory on the invasive plant, Centaurea maculosa, does not reduce its competitive effects on conspecifics and natives

Herbivory can have negative, positive, or no effect on plants. However, insect biological control assumes that herbivory will negatively affect the weed and release natives from competition. Centaurea maculosa, an invader in North America, is tolerant to herbivory, and under some conditions, herbivory may increase its competitive effects on natives. Therefore, we investigated two hypotheses: 1) herbivory stimulates compensatory growth by C. maculosa, which increases its competitive effects, and 2) herbivory stimulates the allelopathic effect of C. maculosa. In the greenhouse, Trichoplusia ni shoot herbivory reduced C. maculosa biomass when shoot damage exceeded 40% of the total original leaf area. Conspecific neighbors had no effect on C. maculosa biomass, and the presence of the natives Festuca idahoensis and F. scabrella had a positive effect on C. maculosa. Neighbors did not alter the effects of shoot herbivory. More importantly, even intense shoot herbivory on C. maculosa did not benefit neighboring plants. In a field experiment, clipping 50% of C. maculosa aboveground biomass in the early summer and again in the late summer reduced final biomass by 40% at the end of the season; however, this clipping did not affect total biomass production or reproductive output. Festuca idahoensis neighbors did not increase the effects of clipping, and aboveground damage to C. maculosa did not release F. idahoensis from competition. In the greenhouse we used activated carbon to adsorb allelochemicals, which reduced the competitive effects of C. maculosa on F. idahoensis but not on F. scabrella or other C. maculosa. However, we found no increase in the allelopathic effects of C. maculosa after shoot herbivory. In summary, our results correspond with others indicating that exceptionally high intensities of herbivory are required to suppress C. maculosa growth and reproduction; however, even intense herbivory on C. maculosa does not insure that native bunchgrasses will benefit.     

Production of male flowers does not decrease with plant size in insect-pollinated Sagittaria trifolia, contrary to predictions of size-dependent sex allocation

It has been proposed that relative allocation to female function increases with plant size in animalpollinated species.Previous investigations in several monoecious Sagittaria species seem to run contrary to the prediction of size-dependent sex allocation (SDS),throwing doubt on the generalization of SDS.Plant size,phenotypic gender,and flower production were measured in experimental populations of an aquatic,insect-pollinated herb Sagittaria trifolia (Alismataceae) under highly different densities.The comparison of ramets produced clonally can reduce confounding effects from genetic and environmental factors.In the high-density population,48％ of ramets were male without female flowers,but in the low-density population all ramets were monoecious.We observed allometric growth in reproductive allocation with ramet size,as evident in biomass of reproductive structures and number of flowers.However,within both populations female and male flower production were isometric with ramet size,in contrast to an allometric growth in femaleness as predicted by SDS.Phenotypic gender was not related to ramet size in either population.The results indicated that large plants may increase both female and male function even in animal-pollinated plants,pointing towards further studies to test the hypothesis of size-dependent sex allocation using different allocation currencies.     

Reproductive parameters vary with social and ecological factors in the polygynous ant Formica exsecta

Due to their haplo‐diploid sex determination system and the resulting conflict over optimal sex allocation between queens and workers, social Hymenoptera have become important model species to study variation in sex allocation. While many studies indeed reported sex allocation to be affected by social factors such as colony kin structure or queen number, others, however, found that sex allocation was impacted by ecological factors such as food availability. In this paper, we present one of the rare studies that simultaneously investigated the effects of social and ecological factors on social insect nest reproductive parameters (sex and reproductive allocation, nest productivity) across several years. We found that the sex ratio was extremely male biased in a polygynous (multiple queens per nest) population of the ant Formica exsecta. Nest‐level sex allocation followed the pattern predicted by the queen‐replenishment hypothesis, which holds that gynes (new queens) should only be produced and recruited in nests with low queen number (i.e. reduced local resource competition) to ensure nest survival. Accordingly, queen number (social factor) was the main determinant on whether a nest produced gynes or males. However, ecological factors had a large impact on nest productivity and therefore on a nest's resource pool, which determines the degree of local resource competition among co‐breeding queens and at what threshold in queen number nests should switch from male to gyne production. Additionally, our genetic data revealed that gynes are recruited back to their parental nests after mating. However, our genetic data are also consistent with some adult queens dispersing on foot from nests where they were produced to nests that never produced queens. As worker production is reduced in gyne‐producing nests, queen migration might be offset by workers moving in the other direction, leading to a nest network characterized by reproductive division of labour. Altogether our study shows that both, social and ecological factors can influence long‐term nest reproductive strategies in insect societies.     

Ovulation does not constrain egg parcel size in the simultaneous hermaphrodite Serranus subligarius

Among egg trading hermaphrodites, any factor which limits the number of eggs released by a female role hermaphrodite can potentially limit the mating success of the male role hermaphrodite fertilizing those eggs. This work examines the hypothesis that the timing of ovulation constrains the size of egg parcels and thereby limits male mating success in the egg parceling hermaphroditic fish Serranus subligarius. Two alternatives were evaluated: (1) Ovulation is a discrete event preceding spawning. It does not constrain the size of egg parcels and therefore does not limit mating success of male role partners. (2) Ovulation is an incremental process occurring throughout the spawning period. It limits the number of eggs available for release in each parcel and thereby limits mating success of the male role partner. Assessment of ovulation was conducted in a field stock of S. subligarius. Fish from size matched pairs were manually stripped at the onset of the spawning period or quarantined and sampled at the end of the spawning period. Fish sampled at either time point had the same number of eggs, suggesting that ovulation was a discrete event occurring at the onset of the spawning period. The diurnal cycle of ovulation was observed in naturally spawning hermaphrodites captured at intervals throughout the day. Ovulation began 2–4 h before spawning began. Some fish appeared to ovulate the entire day's clutch of eggs before spawning, while other fish released egg parcels before completing ovulation. I conclude that the pattern of ovulation is not uniform throughout the spawning stock. Because of the variability in timing of ovulation relative to parcel release, ovulation does not consistently limit the size of egg parcels and therefore is unlikely to be a physiological limit to male role mating success in S. subligarius hermaphrodites.     

An invasive Mimosa in India does not adopt the symbionts of its native relatives

Background and Aims

The large monophyletic genus Mimosa comprises approx. 500 species, most of which are native to the New World, with Central Brazil being the main centre of radiation. All Brazilian Mimosa spp. so far examined are nodulated by rhizobia in the betaproteobacterial genus Burkholderia. Approximately 10 Mya, transoceanic dispersal resulted in the Indian subcontinent hosting up to six endemic Mimosa spp. The nodulation ability and rhizobial symbionts of two of these, M. hamata and M. himalayana, both from north-west India, are here examined, and compared with those of M. pudica, an invasive species.

Methods

Nodules were collected from several locations, and examined by light and electron microscopy. Rhizobia isolated from them were characterized in terms of their abilities to nodulate the three Mimosa hosts. The molecular phylogenetic relationships of the rhizobia were determined by analysis of 16S rRNA, nifH and nodA gene sequences.

Key Results

Both native Indian Mimosa spp. nodulated effectively in their respective rhizosphere soils. Based on 16S rRNA, nifH and nodA sequences, their symbionts were identified as belonging to the alphaproteobacterial genus Ensifer, and were closest to the ‘Old World’ Ensifer saheli, E. kostiensis and E. arboris. In contrast, the invasive M. pudica was predominantly nodulated by Betaproteobacteria in the genera Cupriavidus and Burkholderia. All rhizobial strains tested effectively nodulated their original hosts, but the symbionts of the native species could not nodulate M. pudica.

Conclusions

The native Mimosa spp. in India are not nodulated by the Burkholderia symbionts of their South American relatives, but by a unique group of alpha-rhizobial microsymbionts that are closely related to the ‘local’ Old World Ensifer symbionts of other mimosoid legumes in north-west India. They appear not to share symbionts with the invasive M. pudica, symbionts of which are mostly beta-rhizobial.