Seasonality and colony-size effects on the life-history characteristics of Rhytidoponera metallica in temperate south-eastern Australia

2003 ◽  
Vol 51 (6) ◽  
pp. 551 ◽  
Author(s):  
Melissa L. Thomas

In social insects, colony growth is assumed to follow a logistic growth curve, with small, newly founded colonies experiencing exponential growth (ergonomic stage) that slows down with increasing colony size and approaches an asymptote when the colony produces sexuals (reproductive stage). Environmental factors may also influence colony growth, particularly in temperate climates where colder temperatures in winter slow development. However, growth patterns are rarely studied in detail in social insects. In this study, I investigated colony size and seasonality effects on life-history parameters of the ponerine ant Rhytidoponera metallica. I followed the growth of 10 laboratory colonies monthly over two years in conjunction with monthly excavations of 5 field colonies. Colony composition was highly seasonal in both laboratory and field colonies, with pupae and larvae produced only during the warmer months. Males, however, were present in colonies throughout most of the year. An expected logistic growth pattern was found in the majority (4 of 6) of laboratory colonies that had positive growth, one colony followed a Gompertz growth pattern and another a power curve. Two laboratory colonies decreased in size and two colonies didn't change in size. The slowing of growth observed with increasing colony size in the majority of laboratory colonies was related to a decrease in per capita brood production with increasing colony size. Colony size also related to the presence of males: field colonies containing males were significantly larger than field colonies where males were absent. By using a combination of laboratory and field colonies, I was able to obtain information on seasonality of brood and male production, in addition to important demographic data on mortality and natality rates that is difficult to obtain in social insects using only field excavations.

1991 ◽  
Vol 65 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Dong-Jin Lee ◽  
Robert J. Elias

The upper surface of the corallum ofCatenipora rubrawas often at or just above the sediment-water interface during life. The vertical growth rate was barely sufficient to keep pace with background sedimentation and possible subsidence of the corallum. Therefore, the colonies were in constant danger of being covered by influxes of sediment, especially during storms. This was compensated by the ability of polyps to respond to sedimentation events and by certain aspects of colony growth. Rapid regeneration following partial mortality involved budding of uninjured polyps and rejuvenation of damaged individuals, in some cases accompanied by a type of axial increase not previously known in tabulate corals. Rapid lateral expansion was possible because small, “immature” polyps could bud and grow in a reptant manner.Interconnected ranks of the cateniform corallum served to dam shifting sediment at the periphery of the colony. Lacunae within the colony were reservoirs for material that breached peripheral ranks and for sediment that settled on the ranks and was rejected by polyps or removed by passive flow. Polyps comprising the colony were distributed over a large area of the substrate surface, thereby decreasing the probability of complete mortality during sedimentation events and increasing the probability that a sufficient number of individuals would survive to ensure optimum regeneration. The corallum, anchored in the substrate and with sediment filling the lacunae, provided a broad, stable base during high-energy events.It remains to be established how widespread these growth patterns and strategies were among other corals with cateniform colonies, a form that appeared in many unrelated stocks. Most previous workers emphasized physical strength when considering functional morphology, following a tacit assumption that the corallum rose high above the substrate and was therefore susceptible to breakage during high-energy events. An understanding of the origin of cateniform patterns and the phylogeny of these corals requires knowledge of their modes of growth and life-history strategies, which were genetically as well as environmentally controlled.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Silu Lin ◽  
Jana Werle ◽  
Judith Korb

AbstractOrganisms are typically characterized by a trade-off between fecundity and longevity. Notable exceptions are social insects. In insect colonies, the reproducing caste (queens) outlive their non-reproducing nestmate workers by orders of magnitude and realize fecundities and lifespans unparalleled among insects. How this is achieved is not understood. Here, we identified a single module of co-expressed genes that characterized queens in the termite species Cryptotermes secundus. It encompassed genes from all essential pathways known to be involved in life-history regulation in solitary model organisms. By manipulating its endocrine component, we tested the recent hypothesis that re-wiring along the nutrient-sensing/endocrine/fecundity axis can account for the reversal of the fecundity/longevity trade-off in social insect queens. Our data from termites do not support this hypothesis. However, they revealed striking links to social communication that offer new avenues to understand the re-modelling of the fecundity/longevity trade-off in social insects.


Author(s):  
Harvey C Freetly ◽  
Robert A Cushman ◽  
Gary L Bennett

Abstract The period of heifer development is a relatively small fraction of a cow’s life; however, her pattern of growth may have permanent effects on her productivity as a cow. We hypothesized that altering the growth pattern during the peri-pubertal period would increase life-time productivity across genetic types of Bos taurus cows. The objective was to determine the stayability, calf production, and weight of calf weaned across six calf crops. Heifers (n = 685) were placed on one of two developmental programs at 256 ± 1 d of age. Control heifers received a diet that provided 228 kcal ME·(BW, kg) -0.75 daily, and Stair-Step heifers were allocated 157 kcal ME·(BW, kg) -0.75 daily for 84 or 85 d, and then the daily allocation was increased to 277 kcal ME·(BW, kg) -0.75. Stair-Step heifers (0.33 ± 0.02 kg/d) had a lower ADG than Control heifers (0.78 ± 0.02 kg/d; P < 0.001) during Period 1, and Stair-Step heifers (0.93 ± 0.03 kg/d) had a greater ADG than Controls (0.70 ± 0.03 kg/d; P < 0.001) during Period 2. There were no treatment (P = 0.28) or breed type differences (P = 0.42) for the proportion of cows weaning a calf; however, the proportion of cows weaning a calf decreased with cow age (P < 0.001). Calves from Stair-Step dams had heavier weaning weights (193 ± 1 kg) compared to Control calves (191 ± 1 kg; P = 0.007). There was not a treatment (P = 0.25) or breed type differences in cumulative BW weaned (P = 0.59). A diverse genetic population of cattle within Bos taurus was tested and responses in calf production did not differ between Stair-Step growth pattern and a more constant non-obese growth pattern.


2004 ◽  
Vol 55 (3) ◽  
pp. 295 ◽  
Author(s):  
A. J. Richardson ◽  
J. E. Growns ◽  
R. A. Cook

Caridean shrimps are an integral component of lowland river ecosystems in south-eastern Australia, but their distributions may be affected by flow alteration. Monthly shrimp samples were collected from slackwaters in three hydrologically distinct sections of the heavily regulated Campaspe River and the less regulated Broken River for three consecutive years. The distributions of Paratya australiensis, Caridina mccullochi and Macrobrachium australiense, along with their life history in river sections with different hydrology are outlined. Paratya australiensis and M. australiense occurred in all sections, but C. mccullochi was absent from sections of the Campaspe River that received irrigation flows during summer/autumn. Shrimp larvae were most abundant in summer (December–February) and juvenile recruitment continued through to mid autumn (April). Breeding and recruitment of P. australiensis occurred for longer than other shrimps. Apart from large adult and berried M. australiense, all life stages of shrimps commonly occurred in slackwaters, particularly the larval and juvenile stages. Irrigation flows in summer/autumn probably adversely affect the size, extent and arrangement of slackwaters, at a time when they may be critical habitats for C. mccullochi larval development and recruitment. Dams and weirs in the Campaspe River may have influenced shrimp abundance and the timing of breeding.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Maria Rita Giuca ◽  
Marco Pasini ◽  
Sara Drago ◽  
Leonardo Del Corso ◽  
Arianna Vanni ◽  
...  

Introduction. The Herbst device is widely used for correction of class II malocclusions; however, most of the researches carried out on the Herbst appliance in literature do not take into account patients with a different mandibular divergence. The aim of this study was to investigate the effects of Herbst on dental and skeletal structures and to evaluate possible influence of vertical facial growth patterns. Methods. A retrospective study was conducted on lateral cephalograms of 75 growing patients (mean age: 9.9 ± 1.9 years) with class II malocclusion treated with Herbst. Subjects were divided into 3 groups using the mandibular divergence index (SN and GoMe angle). Cephalometric parameters were evaluated using the modified SO (sagittal occlusion) Pancherz’s analysis. A statistical analysis was conducted to evaluate differences among groups using ANOVA. Results. Our study showed differences in response to treatment depending on patient’s facial vertical growth pattern. Cranial base angle and mandibular rotation were significantly different (p<0.05) between hypodivergent patients and normodivergent patients and between hypodivergent and hyperdivergent subjects. Conclusion. Hypodivergent patients increased their mandibular divergence during treatment to a greater extent than normodivergents; moreover, hyperdivergent patients exhibited a decreased mandibular divergence at the end of the treatment.


2017 ◽  
Vol 6 (4) ◽  
pp. 98-102
Author(s):  
Anatoliy Sergeevich Shumilov ◽  
Sergey Alexandrovich Blagodatsky

The aim of this work was to simulate the growth and spatial structure of the fungal mycelium using a cellular automaton based on the synthesis of various model approaches. The spatial structure of the mycelium is described in the structural submodel of the cellular automaton, which determines the growth rate in the direction of larger resource amount and the number of branches of the mycelium per area unit. The amount of available substrate determines the probability of unidirectional apical growth. Another, biochemical part of the model allows us to describe the rate of transport of resources into the cell, their transport within the mycelium, and also their excretion, and is intended to describe the vertical and horizontal migration in the soil of two nutrients. The proposed model makes it possible to quantitatively describe such a feature of fungal colony growth as more active absorption of resources by external cells, compared to central ones due to separation of transport resources into active and passive resources. The active transport was described using the Michaelis-Menten kinetics. We were able to simulate the stockpiling of surplus resources and their redistribution over the mycelium after the exhaustion of reserves in the external environment, and also to simulate typical growth patterns of mycelial colonies that were observed in experiments published in the literature.


2019 ◽  
Vol 1 ◽  
pp. 1-1
Author(s):  
Shyamantha Subasinghe

<p><strong>Abstract.</strong> Urban growth is a complex process created through the interaction of human and environmental conditions. The spatial configuration and dynamic process of urban growth is an important topic in contemporary geographical studies (Thapa and Murayama, 2010). However, urban growth pattern recognition is a challengeable task and it has become one of the major fields in Cartography. Since classical era of cartography, several methods have been employed in modelling and urban growth pattern recognition. It shows that there is no agreement among cartographer or any other spatial scientists on how to map the diverse patterns of urban growth.</p><p>Typical urban theories such as von Thünen’s (1826) bid-rent theory, Burgess’s (1925) concentric zone model, Christaller’s (1933) central place theory, and Hoyt’s (1939) sector model explain the urban structure in different manner. Most of them do not contribute to visualize the urban growth pattern spatiotemporally. Recently, by addressing this limitations, several sophisticated methods are used in urban growth visualization. Among them, morphological spatial pattern analysis (MSPA) is one of emerging raster data analysis methods which allows us to integrate neighbourhood interaction rules in urban growth pattern recognition and visualization. Angel et al. (2010) developed urban land classification (urban, suburban, rural, fringe open space, exterior open space, and rural open space) based on built and non-built land categories and detected three major types of urban growth (infill, extension, and leapfrog). However, developing urban land classifications using binary land use type and recognising only three types of urban growth pattern may be insufficient due to the existence of a higher complexity of urban growth. In such context, the present study introduce a geovisualization approach to map spatial patterns of urban growth using multiple land categories and develops three sub-levels of urban growth pattern for each major urban growth pattern.</p><p>The entire process of urban growth pattern recognition developed in this study can be summarized into three steps (Figure 1): (1) urban land mapping &amp;ndash; Landsat imageries representing two time points (2001 and 2017) were classified into two land categories (built and non-built) and developed into multiple classes using ancillary data, (2) recognizing three major patterns of urban growth (infill, extension, and leapfrog) &amp;ndash; the raster overlay method based on neighbourhood interaction rules, (3) development of sublevels of urban growth &amp;ndash; major three patterns were further developed and visualized nine urban growth patterns, namely low infill (LI), moderate infill (MI), high infill (HI), low extension (LE), moderate extension (ME), high extension (HE), low leapfrog (LL), moderate leapfrog (ML), and high leapfrog (HL). The developed procedure of this study in urban growth pattern recognition was tested using a case study of Colombo metropolitan area, Sri Lanka.</p>


2021 ◽  
Vol 9 ◽  
Author(s):  
Abel Bernadou ◽  
Boris H. Kramer ◽  
Judith Korb

The evolution of eusociality in social insects, such as termites, ants, and some bees and wasps, has been regarded as a major evolutionary transition (MET). Yet, there is some debate whether all species qualify. Here, we argue that worker sterility is a decisive criterion to determine whether species have passed a MET (= superorganisms), or not. When workers are sterile, reproductive interests align among group members as individual fitness is transferred to the colony level. Division of labour among cooperating units is a major driver that favours the evolution of METs across all biological scales. Many METs are characterised by a differentiation into reproductive versus maintenance functions. In social insects, the queen specialises on reproduction while workers take over maintenance functions such as food provisioning. Such division of labour allows specialisation and it reshapes life history trade-offs among cooperating units. For instance, individuals within colonies of social insects can overcome the omnipresent fecundity/longevity trade-off, which limits reproductive success in organisms, when increased fecundity shortens lifespan. Social insect queens (particularly in superorganismal species) can reach adult lifespans of several decades and are among the most fecund terrestrial animals. The resulting enormous reproductive output may contribute to explain why some genera of social insects became so successful. Indeed, superorganismal ant lineages have more species than those that have not passed a MET. We conclude that the release from life history constraints at the individual level is a important, yet understudied, factor across METs to explain their evolutionary success.


Sign in / Sign up

Export Citation Format

Share Document