Insect predation reduces the abundance of a nidicolous ectoparasite

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.

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The influence of gibbon primary seed shadows on post-dispersal seed fate in a lowland dipterocarp forest in Central Borneo

Journal of Tropical Ecology ◽

10.1017/s0266467405002257 ◽

2005 ◽

Vol 21 (3) ◽

pp. 255-262 ◽

Cited By ~ 14

Author(s):

Kim R. McConkey

Keyword(s):

Seed Fate ◽

Central Kalimantan ◽

Fruit Abundance ◽

Seed Shadow ◽

Dipterocarp Forest ◽

Lowland Dipterocarp Forest ◽

Seed Shadows ◽

Insect Predation ◽

Dispersal Events

The natural seed shadow created by gibbons (Hylobates mulleri×agilis) in Central Kalimantan, Indonesia, was monitored over 11 mo to discern the role of gibbons and post-dispersal events in the spatial pattern of seed germination. Variability in the content and distribution of 183 scats was used to determine which, if any, scat characteristics influenced seed fate. Nine scat characters were evaluated: (1) seed number; (2) number of seed species per scat; (3) scat weight; (4) seed load; (5) rainfall; (6) scat density; (7) distance to nearest fruiting tree; (8) ripe fig abundance; (9) non-fig fruit abundance. More than 99% of monitored seeds were killed, removed, or had germinated during the monitoring period. Vertebrates killed or removed most seeds (86%) and the probability of them moving seeds was highly dependent on non-fig fruit abundance at the time of deposition; factors (2), (6) and (7) also influenced seed removal/predation by vertebrates, depending on whether seeds were deposited in peak or non-peak times of consumption. Insect predation (2% of seeds) occurred mainly in scats that were deposited in months of high ripe fig abundance, while the actual chance of a seed germinating (11% of seeds) was influenced by non-fig fruit abundance at time of deposition and number of species in the original scat. The gibbon-generated seed shadow was profoundly altered by post-dispersal events and variation in the characteristics of the shadow had little lasting impact on the probability of seeds germinating.

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Climate-induced abortion and predation: reproductive success of the pioneer shrubDillenia suffruticosain Malaysian Borneo

Journal of Tropical Ecology ◽

10.1017/s0266467415000632 ◽

2015 ◽

Vol 32 (1) ◽

pp. 50-62 ◽

Cited By ~ 1

Author(s):

Yuji Tokumoto ◽

Michiko Nakagawa

Keyword(s):

Alternative Hypothesis ◽

East Asian ◽

Reproductive Organs ◽

Reproductive Organ ◽

Reproductive Assurance ◽

Tropical Plants ◽

Climate Fluctuations ◽

Excess Production ◽

Immature Seeds ◽

Insect Predation

Abstract:In South-East Asian tropical plants, the excess production of reproductive organs is believed to be controlled by resource booms. However, the continuously flowering shrubDillenia suffruticosa(Dilleniaceae) is often infested by fruit predators and occasionally produces fruits where mature seeds are absent. These reproductive features may support an alternative hypothesis for excess production of reproductive organs: the reproductive assurance hypothesis. We marked 1190 reproductive organs in 180 inflorescences of 41 plant individuals and examined the relationships among the reproductive organ features and the effects of both climate and predators. During the flower budding stage, the fate of reproductive organs was primary climate-induced. The percentage of flower/fruit abscission increased as the cumulative temperature and photosynthetically active radiation (PAR) decreased and the cumulative precipitation increased, supporting the resource boom hypothesis. Insect predation was the most common fate of immature fruits. As PAR increased, the prevalence of insect predation and production of mature seed increased. At a reduced PAR, the production of fruits with many immature seeds could serve as compensatory reproductive organs for insect predators, consistent with the reproductive assurance hypothesis. The excess production of reproductive organs might be a result of adaptation to climate fluctuations in the South-East Asian tropics.

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Mouse killing, insect predation, and conspecific attack by rats with differing prior aggressive experience

Physiology & Behavior ◽

10.1016/0031-9384(85)90063-0 ◽

1985 ◽

Vol 34 (4) ◽

pp. 645-648 ◽

Cited By ~ 10

Author(s):

Ernest D. Kemble ◽

Kevin J. Flannelly ◽

Holly Salley ◽

Robert J. Blanchard

Keyword(s):

Mouse Killing ◽

Insect Predation

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The role of leaf traits and bird-mediated insect predation on patterns of herbivory in a semiarid environment in central Mexico

Botanical Sciences ◽

10.17129/botsci.812 ◽

2017 ◽

Vol 95 (2) ◽

pp. 189 ◽

Cited By ~ 1

Author(s):

Betsabe Ruiz-Guerra ◽

Erika Nieves-Silva ◽

Roger Guevara

Keyword(s):

Structural Characteristics ◽

Insect Herbivory ◽

Leaf Traits ◽

Arid Environments ◽

Plant Associations ◽

Main Driver ◽

Closed Canopy ◽

One Year ◽

Insect Predation ◽

Leaf Strength

Background. In arid environments plants face aridity and herbivory, therefore it has been proposed that both are convergent selective forces. However the drivers of insect herbivory in these ecosystems remain poorly understood.Question. Does insect herbivory vary in two plant associations subject to different levels of aridity? To what extent differences in herbivory are determined either by foliar traits, or predation by birds?Study species. Citharexylum tetramerum, Viguiera pinnatilobata, and Solanum tridynamum.Study site. We compared two-plant associations: the mezquital with a closed canopy and wettest conditions and the tetechera a dry place with an open canopy at the Zapotitlán Valley, México. Methods. We evaluated leaf traits (N, C, water content, leaf strength and trichomes), herbivore insects abundance and the effects on herbivory when some predators are excluded.Results. Herbivory was higher in the drier site (tetechera) than in the more humid one (mezquital) in one year but not in the second one. In both plant associations herbivory increased when predators of herbivores were excluded. Plants in mezquital had more water and nitrogen content than plants in tetechera. The later had higher carbon concentration and carbon:nitrogen ratio, leaf strength and density of trichomes. Abundance of herbivore insects and insect predation were higher in the most arid site. Conclusions. Our results show that insect herbivory increases in the most arid site and that predation by birds plays a role as a driver of herbivory, while resistance to aridity seems to be the main driver of leaf structural characteristics.

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