Toomas Tammaru

University of Tartu · Institute of Ecology and Earth Sciences

Seasonal generations of short-lived organisms often differ in their morphological, behavioural and life history traits, including body size. These differences may be either due to immediate effects of seasonally variable environment on organisms (responsive plasticity) or rely on presumably adaptive responses of organisms to cues signalizing forthc...

1. The allometric relationship between growth rate and body mass has received considerable attention but different taxa have not been equally studied. In particular, a limited amount of information is available on growth allometry of insect larvae. 2. In life-history studies, it is often assumed that insect larvae grow exponentially. This leads one...

In order to facilitate the study of the evolution of female flightlessness among the geometrid subfamily Ennominae (Lepidoptera, Geometridae), we carried out a phylogenetic analysis based on a morphological data matrix, and DNA sequences. We used seven nuclear gene fragments, elongation factor 1alpha (EF-1alpha), wingless (wgl), isocitrate dehydrog...

. Populations of herbivorous insects are considered to be primarily regulated by natural enemies. However, little is known about the ecological role of entomopathogenic fungi. There is very little data on the diversity and prevalence of fungal pathogens in natural insect populations. In this study, the percentage mortality attributable to fungal pa...

Temperature has a profound effect on the growth and development of ectothermic animals. However, the extent to which ecologically driven selection pressures can adjust thermal plastic responses in growth schedules is not well understood. Comparing temperature‐induced plastic responses between sexes provides a promising but underexploited approach t...

Describing fauna is an urgent task due to the current rapid destruction of natural tropical forest ecosystems. However, the majority of tropical insects still remain insufficiently explored in terms of their taxonomy and ecology due to the difficulties in obtaining the data. Since 2011 we have been carrying out fieldwork in Kibale National Park in...

Immature stages of insects are vulnerable to various antagonists, including pathogens. While the abiotic factors affecting pathogen prevalence in insect populations are reasonably well documented, much less is known about relevant ecological interactions. We studied the probability of the larvae of three lepidopteran species to die from fungal infe...

1. The degree to which variation in adult food availability affects the population dynamics of a species depends on its position on the capital-income breeding continuum. The long-lived butterflies that feed on fruits as adults constitute an example of Lepidoptera with a high degree of income breeding. 2. For three species of fruit-feeding butterfl...

Natural enemies shape the fate of species at both ecological and evolutionary time scales. While the effects of predators, parasitoids, and viruses on insects are well documented, much less is known about the ecological and evolutionary role of entomopathogenic fungi. In particular, it is unclear to which extent may the spatiotemporal distribution...

Comparative studies on insects can significantly contribute to understanding the evolution of lifespan, as the trait can feasibly be measured in a high number of species. If the evolutionary determinants of longevity were mainly extrinsic (ecological), related species from different habitats should systematically differ in individual lifespans. We...

Ecological and life-history data on the Northern European macromoth (Lepidoptera: Macroheterocera) fauna is widely available and ideal for use in answering phylogeny-based research questions: for example, in comparative biology. However, phylogenetic information for such studies lags behind. Here, as a synthesis of all currently available phylogene...

Nola estonica Õunap sp. nov. (Lepidoptera, Nolidae, Nolinae) is described based on type material from Estonia. The lectotype is designated for Glaphyra atomosa Bremer, 1861, which is reinstated from a subspecies of Nola aerugula (Hübner, [1793]) to a full species: Nola atomosa (Bremer, 1861) stat. rev. The status of these three taxa as separate spe...

If the evolutionary determinants of longevity were mainly extrinsic, related species from different habitats should systematically differ in individual lifespans. Comparative studies of insects can significantly contribute to understanding the evolution of lifespan, as the trait can feasibly be measured in a high number of species. We recorded adul...

Conspecific females and males often follow different development trajectories which leads to sex differences in age at maturity (sexual bimaturism, SBM). Whether SBM is typically selected for per se (direct selection hypothesis) or merely represents a side-effect of other sex-related adaptations (indirect selection hypothesis) is, however, still an...

Understanding how and why some groups have become more species-rich than others, and how past biogeography may have shaped their current distribution, are questions that evolutionary biologists have long attempted to answer. We investigated diversification patterns and historical biogeography of a hyperdiverse lineage of Lepidoptera, the geometrid...

Seasonal polyphenisms are cases in which individuals representing generations occurring in different times of the year systematically differ in their morphological, physiological, and/or behavioral traits. Such differences are often assumed to constitute adaptive responses to seasonally varying environments, but the evidence for this is still scarc...

The knowledge about the diversity and ecological role of entomopathogenic fungi is primarily based on agroecosystems whereas information derived from natural insect populations is much more limited. To contribute to filling this gap, we recorded the prevalence of fungal infections in laboratory rearing experiments with five species of Lepidoptera,...

Juvenile growth trajectories evolve via the interplay of selective pressures on age and size at maturity, and developmental constraints. In insects, the moulting cycle is a major constraint on larval growth trajectories. Surface area to volume ratio of a larva decreases during growth, so renewal of certain surfaces by moulting is likely needed for...

The distribution of butterflies was mapped throughout entire Estonia in 2016 and 2017. Butterflies were surveyed during three phenologically targeted visits at more than 1200 pre-selected sites. In total, over 180 000 individuals belonging to 97 species were recorded. We compare the resulting distribution maps with historical records, and discuss c...

1). Evading predators is a fundamental aspect of the ecology and evolution of all prey animals. In studying the influence of prey traits on predation risk, previous researchers have shown that crypsis reduces attack rates on resting prey, predation risk increases with increased prey activity, and rapid locomotion reduces attack rates and increases...

Our study aims to investigate the relationships of the major lineages within the moth family Geometridae, with a focus on the poorly studied Oenochrominae-Desmobathrinae complex, and to translate some of the results into a coherent subfamilial and tribal level classification for the family. We analyzed a molecular dataset of 1,206 Geometroidea term...

1. Comparative studies on insect life histories are facilitated by the increasing availability of reliable phylogenies but are hampered by the scarcity of comparable data. Fortunately, morphological proxies of some life‐history traits can be measured on preserved specimens. 2. This study compared values of size‐related life‐history traits among a t...

Specificity is one of the fundamental concepts in ecology. Host specificity of phytophagous insects has been of particular interest because of its crucial role in diversification and life-history evolution. However, the majority of tropical insects remain insufficiently explored with respect to their host-plant relations. A lack of respective data...

Sex-specific mechanisms of the determination of insect body sizes are insufficiently understood. Here we use the common heath moth, Ematurga atomaria (Lepidoptera: Geometridae) to examine how larval growth trajectories differ between males and females. We monitored the development of 1379 larvae in controlled laboratory conditions. Sexually dimorph...

The absolute, relative and allometric growth rates, and the rationale behind them. (DOCX)

The recordings of development time (days) and body mass (mg) of the Ematurga atomaria larvae (N = 1379) during their last, 5th instar. (TXT)

Comparing the contributions of 1) sexually dimorphic instantaneous growth rate, and 2) longer development periods of females to the formation of SSD. (DOCX)

Three different integral measures of growth rates of the last (5th) larval instar (mean values±SE) of Ematurga atomaria, a lepidopteran with sexual dimorphism in pupal masses. (DOCX)

Reanalysis of the data of the present article using integral measures of growth rate. (DOCX)

Recent advances in molecular systematics have led to an emerging understanding of the phylogenetic history of the family Geometridae. These studies have basically confirmed the traditional subdivision of the subfamily Larentiinae into tribes but unsolved problems remain. Here we test the monophyly of the tribe Perizomini, and evaluate the division...

Red Lists are very valuable tools in nature conservation at global, continental and (sub-) national scales. In an attempt to prioritise conservation actions for European butterflies, we compiled a database with species lists and Red Lists of all European countries, including the Macaronesian archipelagos (Azores, Madeira and Canary Islands). In tot...

Seasonal polyphenism constitutes a specific type of phenotypic plasticity in which short‐lived organisms produce different phenotypes in different times of the year. Seasonal generations of such species frequently differ in their overall lifespan and in the values of traits closely related to fitness. Seasonal polyphenisms provide thus excellent, a...

Diet breadth and the degree of capital breeding have been established as major determinants of species‐specific ecology of herbivorous insects. Both these variables are related to resource foraging and therefore can be expected to have effects on sensory capacity. However, such effects have remained poorly studied, let alone in phylogenetically exp...

The idea that the fitness value of body colouration may be affected by biochemically mediated trade‐offs has received much research attention. For example, melanisation is believed to interact with other fitness‐related traits via competition for substrates, costs associated with the synthesis of melanin, or pleiotropic effects of the involved gene...

Research on evolutionary forces determining optimal body sizes has primarily relied on experimental evaluation of respective selective pressures. Accounting for among‐species variation through application of phylogenetic comparative methods is a complementary though little used approach. It enables the direct association of body size values with pa...

Evolutionary studies on animal body size have primarily focussed on selective pressures operating during the adult life. In contrast, ontogenetic pathways leading to differently sized adults have received less attention. In the present study, based on a common garden experiment, we report considerable genetic differences in body size among European...

Specificity (= the degree of ecological specialisation) is one of the fundamental concepts of the science of ecology. Ambiguities on how to define and measure specificity have however complicated respective research efforts. Here we propose that, in insects, a behavioural trait –adult oviposition latency in captivity without a favourable host plant...

The aim of the present study was to evaluate host plant and habitat preferences in the Estonian populations of Euphydryas maturna, a regionally polyphagous but often locally specialised butterfly endangered in most parts of its European range. 2. Laboratory trials suggested that Fraxinus excelsior, Viburnum opulus and Melampyrum pratense are plants...

Latitudinal and elevational trends in body size are found in numerous animal taxa, with various adaptive explanations proposed. It is however debatable whether geographic trends in adult body size are accompanied by corresponding differences in juvenile growth rate (= mass gain per unit time). Respective studies have been complicated by conceptual...

Among-population differences in immunological traits allow to assess both evolutionary and plastic changes in organisms' resistance to pathogens. Such knowledge also provides information necessary to predict responses of such traits to environmental changes. Studies on latitudinal trends in insect immunity have so far yielded contradictory results,...

The Nearctic Epirrita pulchraria (Taylor, 1907) was revealed as a sister taxon of the Palaearctic Malacodea regelaria Tengström,1869 in a molecular phylogenetic analysis of the tribe Operophterini. DNA sequence variation in one mitochondrial (COI) and eight nuclear (28S, EF-1α, WGL, GAPDH, RPS5, IDH, MDH, CAD) gene fragments was used in the analysi...

Preliminary phylogeny of temperate and tropical geometrid moths

Both physiologically and ecologically based explanations have been proposed to account for among-species differences in lifespan but they remain poorly tested. Phylogenetically explicit comparative analyses are still scarce, and those that exist are biased towards homoeothermic vertebrates. Insect studies can significantly contribute as lifespan ca...

The degree of ecological specialization plays a crucial role in shaping the structure and functioning of communities. However, comparing specialization within and among groups of organisms is complicated due to methodological issues but also by conceptual and terminological inconsistencies. Environmental predictability has been considered a key det...

In litter-bearing mammals, the environment and social interactions during early life often have a substantial effect on future behaviour of the animal. Most information though derives from lab rodents, pets or farm animals while comparable data are scarce for non-domesticated species, and endangered carnivores in particular. In this study, we focus...

Understanding ecological requirements of endangered species is a primary precondition of successful conservation practice. Regrettably, we know surprisingly little about the life history of numerous threatened insects, and about their use of larval host plants in particular. The brown butterflies (Nymphalidae: Satyrinae) have traditionally been con...

Predictive classifications of life histories are essential for evolutionary ecology. While attempts to apply a single approach to all organisms may be overambitious, recent advances suggest that more narrow ordination schemes can be useful. However, these schemes mostly lack easily observable proxies of the position of a species on respective axes....

Lepidoptera can significantly contribute to understanding the evolution of lifespan as the trait can feasibly be measured in a high number of species from different environments. If the evolutionary determinants of longevity were mainly extrinsic (ecological), related species from different habitats should systematically differ in individual lifesp...

Regionally oligophagous insects are often host plant specialists at smaller geographical scales, so conservation planning should preferably rely on locally derived information. Host use of the endangered butterfly Eu-phydryas aurinia was investigated close to the northern limit of its European distribution. We experimentally studied host preference...

An evolutionary explanation should consider the balance between environmentally-based selective pressures, and the resistance of the organism's phenotype to adaptive evolution, with the latter being captured by the concept of constraint. The limited attention to non-adaptive explanations in evolutionary ecology is at least partly caused by methodol...

Spatiotemporal variation in the degree of melanism is often considered in the context of thermal adaptation, melanism being advantageous under suboptimal thermal conditions. Yet, other mutually nonexclusive explanations exist. Analysis of geographical patterns combined with laboratory experiments on the mechanisms of morph induction helps to unveil...

Optimality models predict that diet-induced bivariate reaction norms for age and size at maturity can have diverse shapes, with the slope varying from negative to positive. To evaluate these predictions, we perform a quantitative review of relevant data, using a literature-derived data base of body sizes and development times for over 200 insect sp...

The species composition of Estonian harvestmen (Opiliones) was revised based on a critical review of published data and examination of the material from the Estonian Malaise Trap Project (EMTP), which is briefly introduced. Four years of collecting (from 2008 to 2011) with “Czech type”Malaise traps from15 localities throughout Estonia resulted in 4...

The aim of this study was to evaluate host plant and habitat preferences of Lycaena dispar, an oligophagous butterfly species endangered in some parts of its European range.In laboratory trials, the females of Estonian populations accepted various species of Rumex as oviposition substrates. Growth performance of the larvae did not differ between th...

The post-glacial recolonisation of northern Europe has left distinct signatures in the genomes of many organisms, both due to random demographic processes and divergent natural selection. However, information on differences in genetic variation in conjunction with patterns of local adaptations along latitudinal gradients is often lacking. In this s...

Volatile organic compounds (VOCs) released by host plants attract gravid European corn borer (ECB) female moths for oviposition. Despite extensive studies, little is known about VOCs emitted by maize under natural conditions or the odorscape of a maize field, particularly at the time of ECB oviposition. Here, we characterized VOCs released by undam...

Although the effects of host plant quality on the performance of polyphagous herbivores are largely uniform across insect taxa, there are various exceptions to this rule. In particular, there are scattered reports of cases in which the relative quality of different hosts differs among larval instars of a single insect species. Such cases are explai...

In North-East Estonia, considerable amounts of toxicants (e.g. polycyclic aromatic hydrocarbons (PAHs), phenols, heavy metals) leach into water bodies through discharges from the oil-shale industry. In addition, natural and anthropogenic hypoxic events in water bodies affect the health of aquatic organisms. Here we report a study on the combined ef...

Most insect populations are exploited by a complex of different parasitoid species, providing ample opportunities for competitive interactions among the latter. Despite this, resource-mediated competition (i.e., exploitative competition) among insect parasitoids remains poorly documented in natural systems. Here we propose a novel way to infer the...

Larvae of the polyphagous geometrid moth Ematurga atomaria show remarkable variation in colouration and patterning. On the basis of a series of laboratory experiments, we showed that the variability - though genetically based in part - involves a substantial environmental component. We transformed the multidimensional variation in colour and patter...

High among-individual variation in mating success often causes problems in conservation breeding programs. This is also the case for critically endangered European mink and may jeopardize the long-term maintenance of the species' genetic diversity under the European mink EEP Program. In this study, breeding success of wild and captive born European...

Background: Sibling herbivore species or host strains specialized to different food plants frequently evolve specific adaptations to their hosts, including host-specific differences in developmental traits (body mass and development time). Such differences may (1) be a consequence of an evolutionary change in relative quality of different hosts, or...

Ultimate causes of phenotypic plasticity in visual appearance are frequently related to increasing the degree of crypsis in a way specific to the environment. The cues used to elicit such plastic responses may be both direct (i.e. straightforward background matching) as well as indirect. In the latter case, cues other than the visual signals from o...

The aim of the present study was to evaluate—in a geographic perspective—the role of host plant as a determinant of habitat quality for Lopinga achine , a satyrine butterfly endangered over much of its European range. Laboratory trials were performed to record host choices made by the ovipositing females as well as by neonate larvae. In rearing...

Numerous studies have suggested a general relationship between the degree of host specialization and body size in herbivorous animals. In insects, smaller species are usually shown to be more specialized than larger-bodied ones. Various hypotheses have attempted to explain this pattern but rigorous proof of the body size-diet breadth relationship h...

The relative roles of genetic differentiation and developmental plasticity in generating latitudinal gradients in life histories remain insufficiently understood. In particular, this applies to determination of voltinism (annual number of generations) in short-lived ectotherms, and the associated trait values. We studied different components of var...

Patterns of variability in quantitative traits across environmental gradients have received relatively little attention in evolutionary ecology. A recent meta-analysis showed that relative phenotypic variability in body size tends to decrease with improving environmental conditions. This pattern was explained by introducing the concept of upper thr...

The theory of life history evolution generally predicts a negative across-environment correlation between development time and size at maturity in response to variations in environmental quality. Deviations from this pattern occur under specific circumstances. In particular, organisms may mature both early and at a small size when (1) some ultimate...

We have studied the phylogeography of the red-listed Palearctic butterfly Lopinga achine (Nymphalidae: Satyrinae) based on 1,450 base pairs of mitochondrial DNA sequences from 86 individuals representing 12 populations. Our results indicate a strong structuring of genetic variation, with among-population differences accounting for ca. 67% of the va...