Garden Laboratory Research Articles

Phylogeography and larval spine length of the dragonfly Leucorhinia dubia in Europe.

Presence or absence of predators selects for different kind of morphologies. Hence, we expect variation in traits that protect against predators to vary over geographical areas where predators vary in past and present abundance. Abdominal larval spines in dragonfly larvae provide protection against fish predators. We studied geographical variation in larval spine length of the dragonfly Leucorrhinia dubia across Western Europe using a phylogenetic approach. Larvae were raised in a common garden laboratory experiment in the absence of fish predators. Results show that larvae from northern Europe (Sweden and Finland) had significantly longer larval spines compared to larvae from western and central Europe. A phylogeny based on SNP data suggests that short larval spines is the ancestral stage in the localities sampled in this study, and that long spines have evolved in the Fenno-Scandian clade. The role of predators in shaping the morphological differences among the sampled localities is discussed.

Chinook salmon emergence phenotypes: Describing the relationships between temperature, emergence timing and condition factor in a reaction norm framework

AbstractWater temperature can have a profound influence on development and distribution of aquatic species. Salmon are particularly vulnerable to temperature changes because their reproductive and early development life phases are spent in freshwater river systems where temperature fluctuates widely both daily and seasonally. Flow regulation downstream of dams can also cause temperature regime changes, which in turn may spur local adaptation of early life‐history traits. In a common garden laboratory incubation experiment, we exposed spring Chinook salmon (Oncorhynchus tshawytscha) embryos to four temperature regimes: warm stable, cold stable, daily variation and below dam. We found that fry from warmer thermal regimes emerged earlier than those from colder regimes both in terms of calendar date and temperature units and that warmer temperatures caused fry to emerge less developed. There was also a significant effect of family on both emergence timing and development level at emergence. By combining measurements of physiological and behavioural traits at emergence and interpreting them within a reaction norm framework, we can better understand which populations might be more vulnerable to altered thermal regimes.

Higher Trophic Levels Overwhelm Climate Change Impacts on Terrestrial Ecosystem Functioning.

Forest floor food webs play pivotal roles in carbon cycling, but they are rarely considered in models of carbon fluxes, including soil carbon dioxide emissions (respiration), under climatic warming. The indirect effects of invertebrates on heterotrophic (microbial and invertebrate) respiration through interactions with microbial communities are significant and will be altered by warming. However, the interactive effects of invertebrates and warming on heterotrophic respiration in the field are poorly understood. In this study we combined field and common garden laboratory approaches to examine relationships between warming, forest floor food web structure, and heterotrophic respiration. We found that soil animals can overwhelm the effects of warming (to 5 degrees Celsius above ambient) on heterotrophic respiration. In particular, the presence of higher trophic levels and burrowing detritivores strongly determined heterotrophic respiration rates in temperate forest soils. These effects were, however, context-dependent, with greater effects in a lower-latitude site. Without isolating and including the significant impact of invertebrates, climate models will be incomplete, hindering well-informed policy decisions.

Breeding biology of guppy fish, Poecilia reticulata (Peters, 1859) in the laboratory

The breeding biology of guppy fish, Poecilia reticulata (Cyprinodontiformes: Poiciliidae) was studied during March 2008 to May 2009 in ‘Zoological garden laboratory’, Curzon Hall campus, Dhaka University. Guppy bred all over the year except in the winter months December and January with a peak period in July. They were viviparous and multiple breeders, i.e., give birth to fry several times in the breeding season. The mean egg diameter was measured to be (1.02±0.08mm) and fecundity was estimated (40-89) per gram of body weight. The gestation period ranged 25-35 days with an average of 28.1±2.12 days. Developmental stages observed under a compound microscope were classified based on the changes in the developing eye, such as optic cup, early-eyed, middle-eyed, late-eyed, very late-eyed etc. It was noticed that tail portion comes out first at birth. The number of fry per brood ranged from 12 to 60. New born fries were observed with transparent or blackish in colour having slender body with jaws developed on mouth and were fully capable of swimming, eating, and avoiding danger. Guppy grew rapidly, attained sexual maturity at 8 -10 weeks and reached full size in 6 months. DOI: http://dx.doi.org/10.3329/jasbs.v39i2.17866 J. Asiat. Soc. Bangladesh, Sci. 39(2): 259-267, December 2013

SEXUAL SELECTION ACCOUNTS FOR THE GEOGRAPHIC REVERSAL OF SEXUAL SIZE DIMORPHISM IN THE DUNG FLY, SEPSIS PUNCTUM (DIPTERA: SEPSIDAE)

Sexual size dimorphism (SSD) varies widely across and within species. The differential equilibrium model of SSD explains dimorphism as the evolutionary outcome of consistent differences in natural and sexual selection between the sexes. Here, we comprehensively examine a unique cross-continental reversal in SSD in the dung fly, Sepsis punctum. Using common garden laboratory experiments, we establish that SSD is male-biased in Europe and female-biased in North America. When estimating sexual (pairing success) and fecundity selection (clutch size of female partner) on males under three operational sex ratios (OSRs), we find that the intensity of sexual selection is significantly stronger in European versus North American populations, increasing with male body size and OSR in the former only. Fecundity selection on female body size also increases strongly with egg number and weakly with egg volume, however, equally on both continents. Finally, viability selection on body size in terms of intrinsic (physiological) adult life span in the laboratory is overall nil and does not vary significantly across all seven populations. Although it is impossible to prove causality, our results confirm the differential equilibrium model of SSD in that differences in sexual selection intensity account for the reversal in SSD in European versus North American populations, presumably mediating the ongoing speciation process in S. punctum.

Ecotypic differentiation between urban and rural populations of the grasshopper Chorthippus brunneus relative to climate and habitat fragmentation

Urbanization alters environmental conditions in multiple ways and offers an ecological or evolutionary challenge for organisms to cope with. Urban areas typically have a warmer climate and strongly fragmented herbaceous vegetation; the urban landscape matrix is often assumed to be hostile for many organisms. Here, we addressed the issue of evolutionary differentiation between urban and rural populations of an ectotherm insect, the grasshopper Chorthippus brunneus. We compared mobility-related morphology and climate-related life history traits measured on the first generation offspring of grasshoppers from urban and rural populations reared in a common garden laboratory experiment. We predicted (1) the urban phenotype to be more mobile (i.e., lower mass allocation to the abdomen, longer relative femur and wing lengths) than the rural phenotype; (2) the urban phenotype to be more warm adapted (e.g., higher female body mass); and (3) further evidence of local adaptation in the form of significant interaction effects between landscape of origin and breeding temperature. Both males and females of urban origin had significantly longer relative femur and wing lengths and lower mass allocation to the abdomen (i.e., higher investment in thorax and flight muscles) relative to individuals of rural origin. The results were overall significant but small (2-4%). Body mass and larval growth rate were much higher (+10%) in females of urban origin. For the life history traits, we did not find evidence for significant interaction effects between the landscape of origin and the two breeding temperatures. Our results point to ecotypic differentiation with urbanization for mobility-related morphology and climate-related life history traits. We argue that the warmer urban environment has an indirect effect through longer growth season rather than direct effects on the development.

Climatic adaptation in an isolated and genetically impoverished amphibian population

The capacity of populations to respond adaptively to environmental change is essential for their persistence. Isolated populations often harbour reduced genetic variation, which is predicted to decrease adaptive potential, and can be detrimental under the current scenarios of global change. In this study, we examined climatic adaptation in larval life history traits in the pool frogRana lessonaealong a latitudinal gradient across the northern distribution area of the species, paying special attention to the isolated and genetically impoverished fringe populations in central Sweden. Larvae from eight populations within three geographic areas (Poland, Latvia and Sweden) were reared under three temperatures (19, 22 and 26°C) in a common garden laboratory experiment. We found clear evidence for latitudinal adaptation inR. lessonaepopulations, larvae from higher latitudes growing and developing faster than low‐latitude ones. Larvae from the Swedish populations were able to compensate for the effects of cooler temperatures and a shorter growth season with genetically higher growth and development rates (i.e. countergradient variation) in the two higher temperature treatments, but there was no difference among the populations at the lowest temperature treatment, which is likely to be close to the temperature limiting growth inR. lessonae. Our results demonstrate that isolated and genetically impoverished populations can be locally adapted, and identify the Swedish fringe populations as a significant conservation unit adapted to the northern environmental conditions.

The Garden Laboratory : Design development of the garden space by the module unit system

The Garden Laboratory : Design development of the garden space by the module unit system

First report of Alternaria alternata causing leaf spot on Stevia rebaudiana

Stevia rebaudiana is a herbaceous perennial plant of the Asteraceae and native to Paraguay. It has been recognized world wide for its excellent sweetening property. In India the plant has been introduced in the states of Maharastra, Tamil Nadu, Karanataka, Rajasthan and West Bengal. For the last three years, during February when temperature ranges from 20–25°C, severe foliar infections were observed in the region of South Bengal. Symptoms initially appeared as small circular spots, light brown in colour. Later, many became irregular and dark brown to grey, while others remained circular with concentric rings or zones. On severely affected leaves several spots coalesced to form large necrotic areas. On older leaves concentric spots were more common at the tips. Leaf spots varied from 2–18 mm in diameter. Conidial dimensions varied from 10–40 × 6–12 mm, mid to dark brown or olive-brown in colour, short beaked, borne in long chains, oval and bean shaped with 3–5 transverse septa. A fungus was isolated on potato dextrose agar media and produced abundant branched septate, brownish mycelia. Conidiophores were simple, olive-brown, septate, variable in length with terminal conidia, which were solitary or in short chains. Conidial characteristics from culture were similar to the conidia isolated from infected plants. Based on the morphological characters, the organism was identified as Alternaria alternata and the identification was confirmed by the Agharkar Research Institute, Pune, India. A pathogenicity test was performed by spraying leaves of 10 healthy, 3-month-old potted S. rebaudiana plants with a spore suspension of 105 conidia per mL. Control plants were sprayed with sterile water. Plants were covered with plastic bags for 10 days and kept in the laboratory garden at 30 ± 20°C. The pathogenicity tests were repeated three times. The first lesions appeared after a period of 12 ± 2 days. The pathogen was consistently reisolated from the lesions. Fungal diseases reported on S. rebaudiana include Erysiphe cichoracearum, Rhizoctonia solani, Sclerotium dephinii, Sclerotium rolfsii, Septoria steviae, Sclerotinia sclerotiorum and A. steviae (Thomas, 2000; Lovering & Reeleeder, 1996; Kamalakannan et al., 2007; Ishiba et al., 1982). This is the first report of A. alternata on stevia in India. Authors are thankful to the Ramakrishna Mission Ashrama, Narendrapur, India for providing facilities to perform field experiments in their Medicinal Plant Garden, as well as thankful to the Directorate of Food Processing Industries and Horticulture, Govt. of West Bengal, India for financial assistance.

At Home in the Field: Smithsonian Tropical Science Field Stations in the U.S. Panama Canal Zone and the Republic of Panama

By the 1960s many biologists affiliated with North American institutions were intent upon establishing a new kind of field station within tropical America. Conditions at such new stations contrasted with those at tropical medicine research centers, commodity-oriented agricultural research stations like those run by the United Fruit Company, or established botanical centers such as the Atkins Garden and Research Laboratory in Cuba. Absent were the arboreta, the crop demonstration plots, full-scale expatriate residences and most home comforts. Absent too were the nearby plantations served by the economic botany practiced at the agricultural stations.

Suitability of the North American Weeds Sesbania exaltata and S. drummondii (Leguminosae) as Hosts for Neodiplogrammus quadrivittatus and Trichapion lativentre (Coleoptera: Curculionidae) in Argentina

Neodiplogrammus quadrivittatus (Oliver) and Trichapion lativentre (Beguin-Billecocq) are 2 South American weevils successfully used for the biological control of Sesbania punicea (Cavanille) Benth. in South Africa. The potential of these insects as control agents for the weeds Sesbania exaltata (Raf.) Rydb. and S. drummondii (Rydb.) Cory in the United States was studied in Argentina. Estimation of adult consumption, the food preference of adult insects on 5 species of Sesbania (3 native hosts and the 2 weeds mentioned above), the capacity of the insects to complete their life cycle on the weeds, and the weed infestation by wild populations in the laboratory garden were studied. The consumption of N. quadrivitattus on both north American weeds did not differ from that on native hosts. Similar consumption was observed for T. lativentre feeding on S. drummondii. S. exaltata showed the lowest consumption. The feeding preference of N. quadrivittatus was similar to that of its natural host plants. In the case of T. lativentre, results on only S. drummondii were comparable to that of its natural hosts. Both insects were able to complete their life cycles on the weeds. In the garden, there was a marked preference by the weevils for S. drummondii. S. exaltata was not attacked by T. lativentre and no test was carried out with N. quadrivittatus. We concluded that both insects are good biocontrol candidates for S. drummondii, whereas only N. quadrivittatus is a promising control agent for S. exaltata.

Host Range of the Argentine Root Borer Carmenta haematica (Ureta) (Lepidoptera: Sesiidae), a Potential Biocontrol Agent for Snakeweeds (Gutierrezia spp) in the United States

Abstract The Argentine root-boring sesiid moth Carmenta haematica (Ureta) is restricted in Argentina to plants of two genera, Grindelia and Gutierrezia (Asteraceae: Astereae). Field examination of 51,622 plants of 67 species of Asteraceae at 286 locations revealed that larvae completed their development only in Grindelia chiloensis (Corn.) Cabrera, Grindelia tehuelches Cabrera, Gutierrezia solbrigii Cabrera, Gutierrezia spathulata (Phil.) Kurtz., and Gutierrezia mandonii (Sch. Bip.) Solbrig. In multiple-choice tests in the laboratory, using cut stems of 37 species in 27 genera and eight tribes of Asteraceae, 93.5% of the neonate larvae that entered stems entered those of 4 species of Grindelia and Gutierrezia and 95.7% entered these plus the 1 other species of the subtribe Solidagininae tested. In no-choice tests using potted plants in the laboratory garden, neonate larvae placed in holes drilled in the stems of 28 species of plants developed to the adult stage only in Gr. chiloensis but reached the fourth instar also in Grindelia pulchella Dun., Gu. solbrigii, and Solidago chilensis Meyen. The no-choice and multiple-choice laboratory tests, interpreted through the three basic elements of host specificity of insects, support the host range observed in the field. C. haematica is the most specific insect yet tested for biological control of snakeweed. It is sufficiently host specific for introduction into quarantine in the United States for further testing and possible future release in the field.

Biology ofPterolonche inspersa (Lep.: Pterolonchidae), a biological control agent forCentaurea diffusa andC. maculosa in the United States

The moth,Pterolonche inspersa (Staudinger) (Lepidoptera: Pterolonchidae), is widely distributed in southern Europe, north Africa, Turkey and the former Soviet Union. It occurs in both thick and scattered stands of knapweeds in disturbed sites, usually on sandy and/or stony soil. Larvae bore in the roots of diffuse and spotted knapweeds (Centaurea diffusa De Lamarck andC. maculosa De Lamarck). There is one generation per year in northern Greece, and larvae feed in the roots for about 11 months during the growing season (August–September, to the following July–August). In the laboratory garden, emergence took place between the second half of July and the end of August, with peak emergence during mid August. In the field, adults were observed from early to late July. Female moths oviposited on rosettes during the first ten days of July and continued through the end of July. Eggs were laid singly or in groups of five or six, firmly attached to the leaves of the host plant. In the laboratory, females mated within 24 hours of emergence and the preoviposition period lasted 2.6±0.8 days. The oviposition period lasted 7.4±2.2 days and the average number of eggs per female was 142.2±59.2. The incubation period was 12±4.7 days; the pupal stage lasted 14.7±2.4 days; and females lived 15.8±2.4 days, while males lived 10.7±1.4 days. First instar larvae failed to survive on economically important Compositae in the generaCynara L.,Helianthus L.,Zinnia L. andCalendula L. (Dunnet al., 1989).

Ian Hamilton Finlay: A Visual Primer

Poet, gardener, and moralist, Ian Hamilton Finlay is also an artist of international stature whose remarkable originality blurs the traditional genre distinctions between painting, sculpture, and architecture. Ian Hamilton Finlay: A Visual Primer will be an indispensable source for readers interested in any aspect of his work. Representing Finlay as both a visual artist and a poet, it brings together the widest range of printed texts, photographs, and environmental work yet assembled to provide a comprehensive overview of his achievements. Finlay became known in the 1960s as Britain's foremost concrete poet and promoted this movement through his Wild Hawthorn Press, which he continues to operate. Yet he is best known for his garden at Stonypath in Lanarkshire, Scotland, one of the most celebrated of modern gardens. Little Sparta, as the garden is now called, is an inland island constantly transformed with Neoclassical specimens relating Finlay's poem structures to a variety of landscape expressions. It uses the simple elements of plants, water, and land forms in which poem structures and emblems are points of focus to provide a visual and aesthetic education for the visitor. In this garden laboratory, Finlay has transformed the poem from something on a printed page to something akin to a work of architecture. The majority of his work (which extends to many media including cards, posters, pamphlets, portfolios, books, and photographs) is carried out in collaboration with craftspeople, artists, photographers, and architects. Like his garden, his works often imply a sharp, uncompromising critique of the contemporary cultural scene. The French critic Yves Abrioux is a member of the editorial board of the magazine Digraphs and has published numerous articles and exhibition catalogs on Ian Hamilton Finlay's work, as well as on contemporary American fiction and literary theory. Stephen Bann is Professor of Modern Cultural Studies at the University of Kent.

Is Enhanced Phloem Unloading in Plants Parasitized by Cuscuta Restricted to the Site of Attachment?

The stem parasite Cuscuta has a deleterious influence, draining substances from the phloem of the host. Using 14C02 it has been shown that Cuscuta is able to withdraw most of the assimilates which normally move from a photosynthesizing host leaf to growing pods and seeds (Wolswinkel, 1974a). From other data (Wolswinkel, 1974ft; 1978) it has been concluded that, in addition to the very efficient absorption system of the parasite as suggested by its anatomical features (Dorr, 1972), there is an enhanced unloading rate from the phloem in transfer of assimilates from host to parasite. In experiments on enhanced phloem unloading, recently infected plants are normally used. Preliminary experiments have shown that in recently infected plants non-parasitized internodes of parasitized plants do not appreciably differ physiologically from the internodes of non-parasitized plants. Therefore, in most experiments, parasitized stem parts have been compared with non-parasitized parts of the same stem. The question has not been answered whether only the site of attachment of the parasite is influenced or adjacent regions of the host stem are also affected. Some data in a previous paper (Wolswinkel, 1974 ft, see table 3) suggest that in stem parts at a distance of a few centimetres from the site of attachment of Cuscuta , enhanced phloem unloading may occur. In a review, Tsivion (1978) has also mentioned that the influence of the parasite is not restricted to the site of haustorial attachment. In new experiments, in which efflux was studied over a longer time, a more detailed study of this question was made. It could not clearly be demonstrated that stem parts adjacent to the site of attachment of Cuscuta are characterized by an efflux pattern which is different from the pattern shown by stem parts farther away from the site of attachment (Wolswinkel, 1979). During our studies on other aspects of efflux from both parasitized and unparasitized stem segments, however, in several experiments efflux patterns were observed which, during the first part of the experiment, were in accordance with the data in our report from 1974. In this communication a new interpretation will be presented for these observations. Cuscuta europaea L. was grown as described earlier (Wolswinkel, 1974 a). Vicia faba L. cv. Witkiem was grown in the laboratory garden during the summer season (plants from which data are presented in Table 1) and in a glasshouse during the winter season (plants from which data are presented in Table 2). In the experiments with labelled solutes 14Cand or 3H-labelled sucrose and some amino acids were used. In the second experiment described here, 14C-sucrose was used. In the first experiment, data on the efflux of both 3H-solutes and 14C-solutes were collected : in that case, a mixture of 14C-L-asparagine and 3H-sucrose was administered

The Garden Laboratory

The Garden Laboratory

Roof garden laboratory for studying insects and soils

Roof garden laboratory for studying insects and soils

Covent Garden Laboratory

FOR the last eleven years, contact has been maintained between the work of the Department of Scientific and Industrial Research on the transport and storage of food and an important branch of industry through the Department's Covent Garden Laboratory in Endell Street, London. This Laboratory has provided an excellent place for keeping under survey the condition of produce passing through our markets generally and for diagnosing or tracing to their source the different types of wastage and deterioration in fruit and vegetables. Samples of fruits showing wastage or abnormal features are collected from the market or are brought to the Laboratory by salesmen. Often the trouble can be diagnosed at once, but sometimes it is desirable to get the diagnosis confirmed by the Low Temperature Research Station at Cambridge or the Ditton Laboratory. The Covent Garden Laboratory also receives for examination samples of consignments of fruits new or comparatively new to Great Britain, such as mangoes, mangosteens and papaws. The interest taken in this work has now made it necessary to leave Endell Street for larger premises, which were opened by Sir Frank Smith on June 28. These are situated on the top floor of Nos. 9–13 Kean Street.