Mammal and insect predation of chemically and structurally defended Mucuna holtonii (Fabaceae) seeds in a Costa Rican rain forest

2010 ◽  
Vol 26 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Erin K. Kuprewicz ◽  
Carlos García-Robledo
Keyword(s):  
Seed Coat ◽  
Field Experiments ◽  
Seedling Survival ◽  
Chemical Defence ◽  
Camera Traps ◽  
Hard Seed ◽  
Seed Predators ◽  
Pecari Tajacu ◽  
Protective Strategies ◽  
Insect Predation

Abstract:To prevent seed losses from predation, plants have developed protective strategies. Seeds may utilize chemical or structural defences to deter predators. Mucuna holtonii (Fabaceae) has large seeds containing a toxic amino acid, L-dopa, and covered with a hard seed coat. Our study assessed the effectiveness of chemical and mechanical seed defences against vertebrate and invertebrate seed predators within Estación Biológica La Selva, Costa Rica. Pre-dispersal insect and fungus attack of M. holtonii seeds was low (95.7% of 1493 seeds were undamaged). Camera traps monitoring 90 marked M. holtonii seeds showed that the collared peccary (Pecari tajacu) consumed 98.6% of 69 removed seeds over 16 d. Field experiments involving 100 seeds with intact and 100 with opened seed coats found that only opened seeds had endosperm removed by Sericomyrmex amabilis ants (0.5–100% of endosperm removed). Shade-house experiments showed that seeds with high amounts of endosperm removed by ants resulted in low germination success and low seedling biomass production. Although M. holtonii seeds are rich in L-dopa, this compound is not an effective chemical defence against mammals that possess foregut fermentation. The seed coat of M. holtonii is an effective structural defence against invertebrate seed predators, preventing endosperm removal and enhancing seedling survival.

scholarly journals Using endocarp-remains of seeds of wild apricot Prunus armeniaca to identify rodent seed predators

2009 ◽  
Vol 55 (6) ◽  
pp. 396-400
Author(s):  
Hongmao Zhang ◽  
Wei Wang
Keyword(s):  
Seed Coat ◽  
Prunus Armeniaca ◽  
Linear Discriminant ◽  
Hard Seed ◽  
Seed Predators ◽  
Quantitative Studies ◽  
Chinese White ◽  
Wild Apricot ◽  
Field Mice ◽  
Hard Seed Coat

Abstract Some rodent-dispersed seeds have a hard seed-coat (e.g.woody endocarp). Specific scrapes or dental marks on the hard seed-coat left by rodents when they eat these seeds can be used to identify seed predators. In this study we measured the morphological traits of endocarp-remains of seeds of wild apricot Prunus armeniaca used by Chinese white-bellied rats Niviventor confucianus and Korean field mice Apodemus peninsulae. We established their Fisher’s linear discriminant functions to separate endocarp-remains between the two predators. A total of 90.0% of the endocarp-remains left by Korean field mice and 88.0% of those left by Chinese white-bellied rats were correctly classified. The overall percentage of correct classification was 89.0%. One hundred and sixty endocarp-remains of unknown what species predated them were classified using the functions. The method may allow more reliable quantitative studies of the effects of Chinese white-bellied rats and Korean field mice on seed consumption and dispersal of wild apricot and this study might be used for reference in other studies of seed predators identification on hard seeds.

scholarly journals Medium and large-sized mammals of the Reserva Ecológica de Guapiaçú, Cachoeiras de Macacu, RJ

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Israel Dias de Carvalho ◽  
Rildo de Oliveira ◽  
Alexandra dos Santos Pires
Keyword(s):  
Atlantic Forest ◽  
Rio De Janeiro ◽  
Camera Traps ◽  
Large Mammals ◽  
Terrestrial Mammals ◽  
Mammal Conservation ◽  
Pecari Tajacu ◽  
Local Extinctions ◽  
Global Threat ◽  
Janeiro State

Medium and large-sized terrestrial mammals develop important functions in ecosystems maintenance. However, this group is the most vulnerable to local extinctions, through habitat loss or hunting. This study inventoried the community of medium and large mammals in the Reserva Ecológica de Guapiaçú (REGUA), Cachoeiras de Macacu, RJ, providing data on species composition, richness and abundance. Species were registered through the use of camera traps, sign survey and visual encounters on pre-existing trails and roads. The study was conducted from January to October 2012, with each month considered as a sample unit. An effort of 1568 cameras-day and 120 km traveled, resulted on 302 records of 22 species of medium and large-sized mammals, belonging to eight orders. This value corresponds to more than three-quarters of the richness described from this group in the Atlantic Forest of Rio de Janeiro state. Five species are under some level of regional, national or global threat. Three game species, Pecari tajacu, Cuniculus paca and Dasyprocta leporina were abundant in the area. The observed richness was comparable to that found in other studies conducted in rain forests. Thus, for its high number of species, including those under some degree of threat, we conclude that REGUA is an important area to mammal conservation, especially in the Atlantic Forest of Rio de Janeiro state.

scholarly journals Native generalist consumers interact strongly with seeds of the invasive wild cucumber (Echinocystis lobata)

NeoBiota ◽  
2019 ◽  
Vol 53 ◽  
pp. 25-39
Author(s):  
Łukasz Dylewski ◽  
Łukasz Myczko ◽  
Dean E. Pearson
Keyword(s):  
Intraspecific Competition ◽  
Native Plants ◽  
Seedling Survival ◽  
Bird Species ◽  
Camera Traps ◽  
Invasion Success ◽  
Alien Plant ◽  
Garrulus Glandarius ◽  
Echinocystis Lobata ◽  
Survival Of Seedlings

When alien plant species arrive in a new environment, they develop novel interactions with native biota that can range from negative to positive. Determining the nature and strength of these interactions is integral to understanding why some aliens are suppressed and others become highly invasive pests. For introduced terrestrial plants, seed and seedling interactions with native biota are crucial, because most nascent populations start from seed. Herein, we explored interactions between native generalist rodent and bird consumers and seeds of the invasive wild cucumber Echinocystis lobata by conducting seed-offering experiments in Poland. We also evaluated how interspecific competition from native plants and intraspecific competition from clustering of E. lobata seed (clustering resembling consumer seed caching) affected survival of seedlings and young plants. Native consumers interacted strongly with E. lobata seeds, with rodents removing 98% of seeds from ground locations and birds removing 24% of elevated seeds. Camera and live traps indicated that striped field mice Apodemus agrarius were the predominant rodent removing seeds. Camera traps and visual observations indicated that great tits Parus major and European jays Garrulus glandarius were the primary bird species removing elevated seeds. While some level of seed removal was likely attributable to seed predation, as indicated by seed coat remains, we also observed evidence that rodents may cache E. lobata seeds and Garrulus glandarius are known to cache and disperse seeds. Monitoring of seedlings indicated that increasing cover of native plants and clustering of E. lobata seedlings both reduced survival of seedlings and young plants due to inter- and intraspecific competition, respectively. Hence, caching by generalist consumers may disperse E. lobata seeds, which are heavy and lack dispersal adaptations, but such caching may also reduce individual seedling survival rates. Fully understanding invasion success of the E. lobata will require evaluating the net effects of generalist consumers on its recruitment and dispersal.

The pattern of seed development and maturation in beach pea (Lathyrus maritimus)

2003 ◽  
Vol 81 (6) ◽  
pp. 531-540 ◽  
Author(s):  
Gurusamy Chinnasamy ◽  
Arya Kumar Bal
Keyword(s):  
Seed Development ◽  
Seed Coat ◽  
Dry Weight ◽  
Growth Stages ◽  
Protein Accumulation ◽  
Grass Pea ◽  
Hard Seed ◽  
Pea Seeds ◽  
Lathyrus Maritimus ◽  
Beach Pea

The developmental patterns of seed, seed coat, and hardseededness were studied in naturally growing crop plants of beach pea (Lathyrus maritimus (L.) Bigel.) at six reproductive growth stages (S1–S6). Grass pea (Lathyrus sativus L.) seeds were used for comparison in some experiments. The accumulation of fresh and dry weight in pod shell and seed of beach pea and pod shell of grass pea followed an almost sigmoidal pattern. However, grass pea seed showed a linear pattern of weight accumulation. During maturation, moisture content of pod shells and seeds decreased because of dehydration. Beach pea seeds were able to germinate precociously at S4. Seeds collected between S1 and S3 failed to germinate because of immaturity, whereas the development of hard seed coats prevented germination in seeds gathered at S5 and S6. An imbibition test revealed that hardseededness completely prevented water absorption of S5 and S6 seeds even after 24 days of soaking. In grass pea, precocious seed germination was observed at S3. However, speed of germination, germination percentage, seedling length and dry weight increased as seeds approached maturity. Lipid and protein accumulation in seeds of both species increased progressively with maturity and showed a positive correlation with seed weight accumulation. In both beach pea and grass pea seeds, S6 was identified as a physiological maturity stage.Key words: beach pea, grass pea, hard seed, imbibition, Lathyrus, seed coat, seed development, water impermeability.

Germination of Seeds From the Fruits of Thryptomene calycina (Myrtaceae)

1993 ◽  
Vol 41 (2) ◽  
pp. 263 ◽  
Author(s):  
DV Beardsell ◽  
RB Knox ◽  
EG Williams
Keyword(s):  
Gibberellic Acid ◽  
Sulphuric Acid ◽  
Seed Coat ◽  
Major Site ◽  
Low Concentrations ◽  
Viable Seeds ◽  
Insect Predation

Freshly fallen fruits of T. calycina contained seeds which were completely dormant; none germinated after 200 days at 20°C. Seeds excised with testas intact from fresh fruits were partially dormant; one-third germinated after 60 days. The dormancy of seeds in freshly fallen fruits was imposed jointly by the fruit and the seed. The major site of the dormancy was however the seed coat since tearing part of it away from seeds excised from fresh fruits resulted in rapid and complete germination. Fruits stored dry in a laboratory at 20°C for 90 days were partially dormant. Nicking the distal end of these fruits enhanced germination. Seeds excised from these laboratory stored fruits had 85 % germination, which indicated a reduction in the seed imposed dormancy. Germination of T. calycina was independent of light and, although the fruits contained large amounts of phenolic material this did not inhibit germination. Fruits weathered in the field for at least 2 years contained less viable seeds, presumably because of insect predation, but these all germinated within 50 days at 20°C. Brief washing of fruits in concentrated sulphuric acid increased germination. Germination was not enhanced by treatment with low concentrations of gibberellic acid in the presence or absence of cytokinin.

Seed and seedling studies of three Trifolium subterraneum var. brachycalycinum lines, in a predominantly summer rainfall environment

1995 ◽  
Vol 35 (8) ◽  
pp. 1101
Author(s):  
GM Lodge
Keyword(s):  
Seed Production ◽  
Field Experiments ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Trifolium Subterraneum ◽  
Summer Rainfall ◽  
Sowing Time ◽  
Buried Seeds ◽  
Initial Seed ◽  
Total Seed

Field experiments were conducted in a predominantly summer rainfall environment to investigate burr burial, seed production, seed characteristics, seedling emergence and survival, and the effects of time of sowing on 3 Trifolium subterraneum var. brachycalycinum lines (cv. Clare and 2 local lines). Each line produced more surface than buried burrs; surface burrs were 59% (range 56-62%) of the total number of burrs recovered and produced 59% of the total seed number. Numbers of seeds per burr were similar for surface and buried burrs, however, buried seeds were 0.97 mg heavier (P<0.05) than surface seeds. Storage for 5 months at 25/60�C decreased hardseed content of surface seed by 50% and buried seed by 70%. Surface and buried seeds stored at 25/25�C for 3 months prior to sowing in trays had a total emergence of <10%, compared with 70% emergence for seeds stored at 25/60�C before sowing. These emergence differences reflected their levels of hardseededness. Numbers of seeds recovered from the soil were not significantly different among lines, declining from about 4200 seeds/m2 after initial seed set to 150 seeds/m2 by the following winter, a 97% decrease. Seed production in the second year increased seed reserves to about 8730 seeds/m2. With no further seed production, levels had declined by 93% in June 1990 and by 99% in May 1991. These data confirm the importance of annual seed production for persistence. Total seedling emergence in summer-autumn accounted for only 10% of the estimated seed production in each year. Seedling survival in summer-autumn 1988-89 was 92.7%, more than double the survival in 1989-90. The effect of sowing time on flowering was always significant, with time to first flower being highest (196 days) for the earliest sowing in March (P<0.05), progressively decreasing (P<0.05) to 108 days for the latest sowing in July. In March, April and May sowings, inflorescence numbers on the first day of flowering were similar at about 120/m2, but increased markedly (P<0.05) for sowing in June or July. However, for the March and July sowings, number of inflorescences at the 9 November 1990 count, were lowest (P<0.05). May or June sowings had the highest number of burrs and seeds (P<0.05), indicating that these may be the best sowing times for maximum seed production in these Trifolium subterraneum var. brachycalycinum lines.

Influence of tillage and crop residue on postdispersal predation of weed seeds

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 184-194 ◽  
Author(s):  
Heather E. Cromar ◽  
Stephen D. Murphy ◽  
Clarence J. Swanton
Keyword(s):  
Seed Predation ◽  
Crop Residue ◽  
Field Experiments ◽  
Biological Weed Control ◽  
Feeding Strategies ◽  
Natural Form ◽  
Common Lambsquarters ◽  
Seed Predators ◽  
No Till ◽  
Weed Seeds

Field experiments were conducted from 1995 to 1997 in southern Ontario to determine the influence of tillage and ground cover on the quantity of postdispersal seed predation of common lambsquarters and barnyardgrass. Ground-dwelling invertebrates were the dominant seed predators and were responsible for 80 to 90% of all seeds consumed. Predation was highest in no-till and moldboard-plowed environments (averaging 32% in both) and lowest in chisel-plowed environments (averaging 24%). This indicates that the relationship between the level of disturbance and predation is nonlinear and that other factors, such as the mobility of invertebrates and food availability, may also play important roles in determining the quantity of seed predation. In no-till, the type of crop residue also influenced the quantity of predation, with highest seed predation found in plots with corn residue (averaging 31%) and lowest in those with soybean and wheat residue (24 and 21%, respectively). It is apparent that there is an optimum combination of residue quantity and quality that maximizes the quantity of seed predation. Based on the experimental design used in this study, no feeding preference by seed predators was detected between common lambsquarters and barnyardgrass. Density-dependent feeding, however, was evident for both species. Most biological control efforts have centered around predators with specific feeding habits. We contend that invertebrates with opportunistic feeding strategies that feed on weed seeds may be the most significant broad spectrum and natural form of biological weed control affecting weed population dynamics. Populations of beneficial arthropods should be conserved, and management strategies that augment the size of their natural populations should be encouraged.

Anatomical structure and nutritive value of lupin seed coats

2001 ◽  
Vol 52 (10) ◽  
pp. 985 ◽  
Author(s):  
Z. H. Miao ◽  
J. A. Fortune ◽  
J. Gallagher
Keyword(s):  
Seed Coat ◽  
Nutritive Value ◽  
Crude Fibre ◽  
Hard Seed ◽  
Anatomical Analysis ◽  
Lupin Seed ◽  
Series Of Experiments ◽  
Selection For ◽  
Growing Conditions ◽  
Seed Coats

Selection and breeding for yield and adaptation to environmental conditions often changes a number of characteristics of crops, and may influence the value of seed for animals. A series of experiments was conducted to evaluate the effect of breeding and growing conditions on the structure and degradability of lupin seed coats. Breeding has had significant influences on both seed size and seed coat structure of lupins. For instance, cultivars of Lupinus angustifolius released in 1987 and 1988 tended to have smaller seeds with a thicker seed coat than those released in 1971 (P < 0.05). Selection for soft seeds has resulted in a reduction of seed coat thickness in L. angustifolius. Hardseeded and roughseeded lines of L. cosentinii had thicker coats (P < 0.05) than softseeded and smoothseeded, respectively. The main contributor to the thick seed coat of hardseeded lines was a layer of cells known as the hourglass layer, which is located between the outer palisade and inner parenchyma. Anatomical analysis revealed that the soft seed coat tended to have short and round cells, whereas the hard seed tended to have long cells in the palisade layer. Smooth seeds had round cells in the subpalisade, but rough seeds had long cells in this layer. Although the seed coats of lupins contained about 80% crude fibre, with L. cosentinii and L. pilosus having more fibre than L. angustifolius, the fibre in lupin seed coats was highly digestible by sheep.

Dormancy in Pinusmonticola seed related to stratification time, seed coat, and genetics

1987 ◽  
Vol 17 (4) ◽  
pp. 294-298 ◽  
Author(s):  
R. J. Hoff
Keyword(s):  
Seed Coat ◽  
White Pine ◽  
Hard Seed ◽  
Physiological Conditions ◽  
Western White Pine ◽  
Minor Site ◽  
Coat Layer ◽  
A Minor ◽  
Hard Seed Coat

The inner layer of the seed coat, a papery membrane, and physiological conditions of the gametophyte–embryo were shown to be major sites of dormancy in seed of western white pine. The hard seed coat layer was a minor site. With no stratification, 7% of the seeds were not dormant, 9% were dormant because of the hard seed coat, 34% were dormant because of the inner seed coat, and 50% were dormant because of physiological conditions of the gametophyte–embryo. These values varied with stratification times and seed lots (families).

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