Reingestion of feces in rodents and its daily rhythmicity

Summary The ingestion of feces is widespread among rodent species and is an extensively employed component of the repertoire of feeding behaviors in some species. Coprophagy is thus a significant consideration in the nutrition and dietary ecology of many rodents. As certain fecal pellets pass from the anus, they are taken up directly into the mouth, chewed, and swallowed. The nocturnally active herbivorous kangaroo rat Dipodomys microps ingests about 1/4 of the feces it produces daily and the daily pattern of reingestion shows a consistent rhythm. For about 8 h of the daytime, during the non-foraging, resting phase of the day, D. microps reingests all fecal pellets produced; during the remainder of the day it leaves all feces produced. The reingested feces contain more nitrogen and water, and less inorganic ions than the non-reingested feces. The extent of reingestion varies among rodent species in relation to diet, and coprophagy is more important in the more herbivorous species. The granivorous kangaroo rat D. merriami ingests feces rarely. The herbivorous vole Microtus californicus ingests about 1/4 of its feces, as does D. microps. However, in contrast to D. microps, M. californicus shows a series of rhythmic, short-term (one to several hour duration) alternations between reingestion and non-reingestion during the course of the day and night. This pattern correlates with the pattern of foraging in M. californicus, which extends over both night and day.     

Chemical aspects of host‐acceptance behaviour in the bird cherry‐oat aphid Rhopalosiphum padi: host‐acceptance signals used by different morphs with the same genotype

Host acceptance by gynoparae and winged virginoparae of the bird cherry‐oat aphid Rhopalosiphum padi (L.) is investigated utilizing leaves and aqueous extracts of the primary and secondary hosts, as well as nonhost plants. Gynoparae are specialized to reproduce on bird cherry Prunus padus L., whereas virginoparae reproduce and feed on various grasses. Host acceptance is assessed using levels of reproduction and survival for adults, as well as survival for nymphs. Little is known of host acceptance by nymphs. The data show that gynoparae and winged virginoparae produce nymphs almost exclusively on their host plants, bird cherry and barley leaves, respectively, over 72 h. When tested with aqueous plant extracts, however, gynoparae produce nymphs almost exclusively on bird cherry extract and progeny numbers are found to be similar to those on plant leaves. Few nymphs are produced on artificial diet. By contrast, winged virginoparae produce nymphs on aqueous extracts of barley, bird cherry and bean, as well as on artificial diet. The numbers of nymphs deposited by gynoparae are similar on aqueous extracts of bird cherry leaves collected at different times during the growing season. When extracts from leaves of various Prunus species are tested, only leaves of P. padus and Prunus virginiana stimulate parturition. Oviparae, the sexual female nymphs of gynoparae, survive well for 96 h on both bird cherry and barley leaves but not on bean seedlings, whereas nymphs of winged virginoparae survive well only on barley leaves. They do not survive for 96 h on any plant‐leaf extracts, although they do survive on artificial diet.     

Diet and feeding patterns in the kipunji (<Emphasis Type="Italic">Rungwecebus kipunji</Emphasis>) in Tanzania’s Southern Highlands: a first analysis

The diet and feeding behaviour of the kipunji (Rungwecebus kipunji) was studied over 45 months, the first dietary analysis for this species. During 9498 h of direct observation of 34 kipunji groups, a list of 122 identified foodplants was recorded. The list represents 60 families, including 64 trees, 30 herbs, 9 climbers, 7 shrubs, 6 lianas, 3 grasses and 3 ferns. Kipunji were observed eating bark, young and mature leaves, ripe and unripe fruits, flowers, pith, seed pods, rhizomes, tubers, shoots and stalks. Invertebrates, fungi, moss, lichen, and soil were also eaten. Macaranga capensis var. capensis, an early successional tree, was the most commonly consumed species, with leaves, leaf stalks, pith, flowers and bark all eaten. We demonstrate that the kipunji is an omnivorous dietary generalist, favouring mature and immature leaves, ripe and unripe fruits and bark in similar proportions, with an almost comparable fondness for leaf stalks and flowers. Kipunji appear to be adaptable foragers able to modify their diet seasonally, being more folivorous in the dry season and more frugivorous in the wet. Whereas more ripe fruit is eaten in the wet season, the proportion of unripe fruit remains similar across the year. The proportion of mature leaves and pith increases throughout the dry season at the expense of ripe fruits and bark, and this may compensate nutritionally for the lack of available dry-season ripe fruits. Relatively more pith is eaten in the dry season, more stalks at the end of the dry and beginning of the wet seasons, and bark consumption increases as the rainfall rises.     

Dietary and Feeding Differences Between Sympatric Propithecus diadema diadema and Indri indri

We analyzed the dietary profiles and feeding behaviors of Propithecus diadema diadema and Indri indri in a community of animals that reside in midaltitude rain forest within Madagascar's Mantadia National Park. Propithecus diadema diadema ate a diverse mixture of fruits, seeds, flowers and young leaves, while the bulk of the diet of Indri indri consisted of young leaves, which resulted in significantly higher levels of fat and water-soluble carbohydrates in foods eaten by Propithecus diadema diadema. Fiber values of items eaten are high (54% NDF) for both species, though not significantly different between them. The preference for immature foliage by Indri indri suggests that their overall intake of fiber is greater than that of Propithecus diadema diadema, which had a high proportion of non-leaf material in their diet. We propose that differences in gut morphology between the two indriids contribute to their disparate diets. Levels of secondary compounds were high in certain food items, but overall they are also not significantly different between the two indriid diets. Propithecus diadema diadema exhibited a strong preference for 2 alkaloid-containing seed species, while no food of Indri indri contained alkaloids. In addition, Propithecus diadema diadema consumed a higher diversity of plant species on a daily/yearly basis, exhibited more feeding bouts on a daily basis, and their feeding bouts (on young leaves, fruit and flowers) are significantly shorter in duration than those of Indri indri. Furthermore, Propithecus diadema diadema had twice the number of geophagic episodes of Indri indri.     

Diet ofColobus polykomos on Tiwai Island: Selection of food in relation to its seasonal abundance and nutritional quality

A group of Colobus polykomosat Tiwai, Sierra Leone, demonstrated seasonal flexibility in its diet, with seeds, young leaves, and mature leaves each dominating the diet at different times. Comparison of food consumption with phenological data indicates that seeds are eaten whenever available and are preferred to other foods, while young leaves are preferred to mature leaves. Colobus polykomosalso prefer liane to tree leaves, despite the relatively high quality of mature tree foliage at the Tiwai site. Analysis of protein, fiber, and energy values of foods selected and items available, but not eaten, suggests that preference is related to protein and energy maximization. Leguminous plants, especially Papilionaceae and Mimosaceae, are highlighted as important food sources for C. polykomos;seeds and leaves from these families have a high nitrogen content, and the protein content of leguminous seeds often equals or exceeds that found in leaves. It is predicted, therefore, that colobines living in habitats with a high density of legumes will feed heavily on seeds, subject to constraints such as seasonal availability. Where suitable leguminous species are less common, a mixture of fruits, seeds, and young or mature leaves or both is likely to be selected. The results of this and other recent studies of colobines do not support the notion that colobines are specialist folivores.     

Mineral ion composition and osmotic relations of Atriplex confertifolia and Eurotia lanata

Summary Periodic collections of Atriplex confertifolia and Eurotia lanata leaf tissue throughout the growing season were analyzed for osmotic potential, water content, and concentration of Na⁺, K⁺, soluble Ca⁺⁺, Cl^-, and SO₄ ^-- ions. Ionic concentrations of these two species exhibited marked similarities to corresponding values for European members of the same genera. Atriplex confertifolia, like many other Atriplex species, behaves as an alkali halophyte and accumulates Na⁺, while E. lanata appears to favor accumulation of K⁺ as did its European counterpart, E. ceratoides.The analyses showed a much broader range of tissue moisture contents and osmotic potentials during the season for Atriplex than for Eurotia. The differences in leaf water relations between the two species are possibly related to the greater NaCl accumulation by Atriplex as compared to Eurotia. An apparent advantage exists for Atriplex in prolonging physiological activity and carbon gain in the dry portion of the late summer by NaCl accumulation.     

Microsite and litter cover effects on seed banks vary with seed size and dispersal mechanisms: implications for revegetation of degraded saline land

Seed movements and fates are important for restoration as these determine spatial patterns of recruitment and ultimately shape plant communities. This article examines litter cover and microsite effects on seed availability at a saline site revegetated with Eucalyptus sargentii tree rows interplanted with 5?C6 rows of saltbush (Atriplex spp.). As litter accumulation decreases with increasing distance from tree rows, soil seed banks were compared between paired bare and litter-covered zones within three microsites; tree row, saltbush row closest to tree row and saltbush mid-row (middle row of saltbush between tree rows). Germinable seed banks of the four most abundant species with contrasting seed sizes and dispersal mechanisms were assessed to test the hypotheses that: (i) microsites with litter cover contain higher seed densities than bare areas, but that (ii) microsite and litter effects will vary depending on seed size and dispersal mechanisms. Overall, litter cover increased seed densities, however, litter effects varied with seed size, with no effect on small-seeded species and litter increasing densities of large-seeded species. Seed bank composition also differed between tree and shrub microsites due to differences in seed morphology and dispersal mechanisms. Water-dispersed species were unaffected by microsite but densities of wind-dispersed species, including Atriplex spp., were higher in saltbush microsites. Densities of wind-dispersed species also differed between the two saltbush microsites despite similar litter cover. Future plantings should consider row spacing and orientation, as well as the dimensions of seeding mounds and associated neighbouring depressions, to maximize litter and seed-trapping by microsites.     

The growth patterns of some hydroids that are obligate epiphytes of seagrass leaves

The growth patterns of the hydroids Campanularia asymmetrica, Sertularia perpusilla and Algaophenia harpago on the Mediterranean seagrass Posidonia oceanica, and of Laomedea angulata on the temperate seagrass Zostera marina, were examined. The seagrass leaves grow from a basal meristem and have a short life which presents problems for these long-lived obligate epiphytes. Downward growth onto younger leaf tissue, shown by S. perpusilla and C. asymmetrica, reduces the risk of interspecific competition with other epiphytes, and places the hydroids on substrates that survive longer than older distal leaf tissue, close to short young leaves which they can colonize by stolon transfer. S. perpusilla was found only on the basal areas of leaves, possibly because of the progressive degeneration of their most apical tissue. C. asymmetrica showed no such degeneration and was found over most of the length of the leaves. The hydrorhizae of most small A. harpago and L. angulata grew both upward and downward along the leaves. Both species were most abundant on the apical halves of older leaves. This distal distribution is considered to be advantageous for these large branched hydroids which are suited for capturing planktonic prey, and to enhance their probability of colonizing neighbouring plants. Its disadvantages include the reduced probability of maintaining the hydroids on the same plant and an increased risk of being eaten by seagrass grazers.     

Folivory by a tropical tanager: species of plants used and the relationship between leaf consumption and fruit abundance

ABSTRACT Folivory, or eating leaves, is unusual for small passerines. Puerto Rican Spindalises (Spindalis portoricensis, Thraupidae), tanagers endemic to the island of Puerto Rico, are known to feed on leaves, but little is known about the possible importance of leaves in their diet. Our objectives were to determine the different species of leaves eaten, the percentage of their diet consisting of leaves, and the relationship between leaf consumption and fruit abundance. We used data from previous studies where the foraging activity of Puerto Rican Spindalises was systematically sampled, and from additional observations made throughout the island. We documented 160 records of folivory, with spindalises feeding on 44 plant species in 25 plant families, including monocots, dicots, gymnosperms, and pteridophytes. Spindalises fed on young leaves of 26 plant species, and mature leaves of 19 plant species. Spindalises were primarly frugivorous (83.9% of diet), but leaves were the second most frequent food item in their diets (8.9% of diet). We also found that leaf consumption was negatively correlated with the abundance of ripe fruit, suggesting that leaves were particularly important food items when less fruit was available. The frequency of folivory by spindalises in our study was less than reported for other folivorous passerines such as plantcutters (Phytotoma spp.) and saltators (Saltator spp.). Nonetheless, folivory may help spindalises cope with human‐dominated landscapes and other environmental changes on small islands.     

Notes on the ecology of buffy saki monkeys (Pithecia albicans,Gray 1860): A canopy seed-predator

Data on the ecology and diet of buffy sakis (Pithecia albicans) were obtained during a 20-month study in an entirely undisturbed terra firme forest in the upper Urucu river, Amazonas, Brazil. Groups of 3–7 sakis found in a 900-ha study plot used large home ranges (147–204 ha), which overlapped extensively with those of neighboring groups. Similar to other pitheciines, buffy sakis were primarily seed predators, relying heavily on young seeds of certain key plant families, such as the Sapotaceae and Leguminosae. Ripe fruits, ripe seeds, young leaves, flowers, and nectar were eaten to a lesser extent. Whether or not feeding, sakis spent most of their time in the canopy and subcanopy, a pattern similar to that of other southwestern Amazonian saki species, but sharply different from that of Guianan sakis (Pithecia pithecia), which use considerably lower levels of the forest. Comparisons are made between different Pithecia species to show whether and how P. albicans diverges ecologically from its congeners. © 1993 Wiley-Liss, Inc.     

Fallback Foods of Red Leaf Monkeys (Presbytis rubicunda) in Danum Valley, Borneo

Animals in Southeast Asia must cope with long periods of fruit scarcity of unpredictable duration between irregular mast fruiting events. Long-term data are necessary to examine the effect of mast fruiting on diet, and particularly on the selection of fallback foods during periods of fruit scarcity. No such data is available for colobine monkeys, which may consume substantial amounts of fruits and seeds when available. We studied the diet of red leaf monkeys (Presbytis rubicunda, Colobinae) in Danum Valley, Sabah, northern Borneo, using 25 mo of behavioral observation, phenology and vegetation surveys, and chemical analysis to compare leaves eaten with nonfood leaves. The monkeys spent 46% of their feeding time on young leaves, 38% on seeds, 12% on whole fruits, 2.0% on flowers, 1.0% on bark, and 1.2% on pith. They spent more time feeding on seeds and whole fruit when fruit availability was high and fed on young leaves of Spatholobus macropterus (liana, Leguminosae) as fallback foods. This species was by far the most important food, constituting 27.9% of the total feeding time, and the feeding time on this species negatively correlated with fruit availability. Consumed leaves contained more protein than nonconsumed leaves, and variation in time spent feeding on different leaves was explained by their abundance. These results suggest that red leaf monkeys show essentially the same response to the supra-annual increase in fruit availability as sympatric monogastric primates, increasing their seed and whole-fruit consumption. However, they depended more on young leaves, in particular Spatholobus macropterus, as fallback foods during fruit-scarce periods than did gibbons or orangutans. Their selection of fallback food appeared to be due to both nutrition and abundance.     

Aspects of the reproductive ecology of four australian Hakea species (Proteaceae) in South Africa

Summary Four shrub species of the Australian Proteaceae (Hakea sericea, H. gibbosa, H. suaveolens and H. salicifolia) were introduced to South African fynbos shrublands between 1840 and 1860. H. sericea is highly invasive, H. gibbosa and H. suaveolens are moderately invasive and H. salicifolia is not invasive. The allocation of reproductive energy, germinability, the ability to survive fires and to germinate in burnt and unburnt areas, and the nutrient content of seeds were assessed for the four species. The information was used to investigate whether the success of H. sericea relative to the other three species could be explained by the superior expression of any trait. The most important trait which separates H. sericea from the other species is its ability to produce a large seed bank in its adopted environment in the absence of seed predators. Seed production in H. sericea shrubs with an above-ground dry mass of 8 kg is four times greater than H. gibbosa and more than 16 times that of H. suaveolens. Although H. salicifolia also produces a large seed bank, its seeds are unable to survive fires due to inadequate insulation by the small follicles. The results are compared to dispersal and seed bank data for indigenous South African Proteaceae, which have low dispersal and suffer high pre-dispersal seed predation. We suggest that potential invasives in the fynbos can be identified as species that have: (i) a potentially high seed production that is limited by specialized predators; (ii) an ability to disperse over long distances; and (iii) are pre-adapted to frequent fires and low soil nutrients. The data also support the current strategy of combatting H. sericea using specialized insect seed predators.     

Diet of two sympatric Pheidole spp. ants in the central Monte desert: implications for seed–granivore interactions

Ants of the genus Pheidole are important seed consumers in several desert ecosystems. In South American deserts, although several Pheidole spp. have been characterized as seed harvesters, studies on their diet and ecological role are still missing. Pheidole spininodis (Mayr) and Pheidole bergi (Mayr) are capable of removing seeds in the central Monte desert. The aim of this study was to quantify and compare the diet of these species and to interpret the results in the context of seed–granivore interactions. Diet was estimated during mid-summer by collecting items brought back to the nest by foragers in ten colonies per species. While P. spininodis was mainly granivorous, P. bergi was mainly insectivorous. However, they both collected ~40% of other types of items. Among seeds, the diet of P. spininodis included mostly grass seeds, whereas the diet of P. bergi was mainly made up of shrub and tree seeds, usually retrieved cooperatively. This behavior allowed P. bergi to carry larger seeds, resulting in diet partitioning in terms of seed size. However, diet of P. spininodis is very similar to that of three sympatric Pogonomyrmex species. Thus, specialized harvester ants remove large quantities of grass seeds in the central Monte desert during the summer, potentially affecting their abundance in the soil seed bank. P. bergi directs its feeding pressure to shrub and tree seeds, and although seeds constitute ~10% of its diet, its high colony density and high activity levels, added to the lower proportion of large seeds in the soil seed bank, indicate that their importance as seed consumers cannot be ruled out.     

The Ecology of Baetis muticus and Baetis rhodani (Insecta,Ephemeroptera), with Special Emphasis on Acid Water Backgrounds

The two mayflies (Insecta, Ephemeroptera) Baetis muticus and Baetis rhodani are absent from the acid water (pH 4.8–5.2) streams of the Upper Duddon drainage basin. Field observations and laboratory experiments were used in an attempt to explain this absence. Baetis muticus could not tolerate acid water; in addition it was deduced that available foods in the Upper Duddon streams would not sustain it there, even if the water could be tolerated. Baetis muticus feeds by browsing on decaying, allochthonous leaves, implying an input of micro-organisms, especially fungi, to the diet. Well-decayed, allochthonous leaves do not occur in the acid water, Upper Duddon streams. Baetis rhodani proved to be acid water tolerant, but only if the background waters had high ionic loadings. Since Upper Duddon waters have only low ionic loadings, Baetis rhodani is apparently excluded from them on this account. The evidence was that if the Upper Duddon waters were chemically suitable, then Baetis rhodani could survive in them, because a suitable food, the alga Hormidium subtile is present.     

Food selection by the silver leaf monkey,Trachypithecus auratus sondaicus,in relation to plant chemistry

Summary Samples of leaves and fruits exploited as food items byTrachypithecus auratus sondaicus were analysed for nitrogen content, acid detergent fibre (ADF), pepsin cellulase digestibility (CDIG), condensed tannins (CT), total phenolics (TP) and protein precipitation capacity (PP) and compared with fruits and leaves not eaten. Differences in chemical measures for items eaten and not eaten were not statistically significant but trends indicate that leaves may have been selected for their lower fibre content and greater digestibility. Fruits eaten also had a higher mean level of CDIG and lower mean level of ADF than fruits not eaten but these measures are not considered to be of major importance in fruit selection as CDIG was lower and ADF higher in fruits eaten than in leaves eaten. Levels of CT, TP and PP capacity were higher in fruits eaten than in fruits not eaten but lower in leaves eaten than in leaves not eaten. The role of tannins and phenolics in food selection is discussed. Leaves (and fruits) were not strongly selected on the basis of protein content. Approximately half the dietary intake ofT. auratus sondaicus was leaves, a protein-rich food source. Possibly, protein levels in foliage at Pangandaran were sufficient that selection for this nutrient was not required. A nutrient other than protein (for example, soluble carbohydrates) may have been maximised through food selection. The protein/ADF ratio may provide an indicator of the acceptability of foliage in a habitat as potential food for a colobine. However, this ratio did not govern food selection byT. auratus sondaicus at Pangandaran.     

Diet of the Indochinese silvered langur (Trachypithecus germaini) in Kien Luong Karst area,Kien Giang Province

The Indochinese silvered langur (Trachypithecus germaini) is distributed to the west of Mekong River in Cambodia, Lao PDR, Thailand and Vietnam. During a two‐year study, from May 2014 to May 2016, we collected 320.44 hr of behavior, with 17,040 feeding bouts recorded (142 hr) for T. germaini on Chua Hang Karst Mountain, Kien Luong District, Kien Giang Province, Vietnam. Feeding accounted for 45% of the Indochinese silvered langurs’ activity budget. The plant diet of the Indochinese silvered langurs was principally composed of young leaves (58%), followed by mature leaves (9.5%), fruits (22.7%), flowers (4.7%), buds (3.3%), petioles (1.2%), and other (0.5%). A total of 58 plant species were fed on by the silvered langurs, and leaves of eight species (Phyllathus reticulatus, Ficus rumphii, Ficus tinctoria, Ficus microcarpa, Cayratia trifolia, Streblus ilicifolia, Combretum latifolium, and Streblus asper) were fed on throughout the year. P. reticulatus was most frequently eaten (13.9% feeding time, n = 1,733). Food selection differed significantly between months and seasons. The Indochinese silvered langurs ate 27 plant species in the wet season compared with 23 plant species in the dry season. Leaf chemical composition of two food categories, 16 eaten species (with 10 most frequently consumed species and six least consumed species), and four noneaten species, were analyzed. Feeding samples from eaten species in the Indochinese silvered langurs's diet contained lower amounts of condensed tannin, lignin, protein, ash, and lipids, but a higher amount of total sugar compared with samples from noneaten species. Furthermore, the most frequently consumed species contained lower amounts of lignin compared with the less frequently consumed species. Using a generalized linear model with five variables, including neutral detergent fiber (NDF), total sugar, lignin, lipid, and calcium (Ca) indicated that NDF positively correlated and lignin content negatively correlated with feeding records in the diet of these langur.     

The functions of plant feeding in the omnivorous predator Dicyphus hesperus: water places limits on predation

1. Dicyphus hesperus Knight (Heteroptera: Miridae) nymphs were fed from egg hatch to the adult stage on Ephestia kuehniella eggs provided either alone or in combination with tomato leaves or with a supplementary water source. 2. Only 6% of individuals completed nymphal development on a diet of eggs alone. In contrast, a high proportion of nymphs completed development on a diet of eggs when either tomato leaves (97%) or a supplementary water source (88%) were provided. 3. The development times of nymphs given access to leaves were significantly shorter than those of nymphs given access only to supplementary water. 4. Adult female D. hesperus that were given access to tomato leaves prior to feeding trials consumed significantly more eggs in a 4‐h period than females that were dehydrated before trials. Dehydrated females that were allowed access to water for 3 h before trials consumed an intermediate number of eggs. 5. Plant feeding or access to some other water source is required for prey feeding, growth, and development in D. hesperus, and acquisition of water is proposed as a primary function of plant feeding. In addition, D. hesperus derives nutrients from plant feeding that increase the rate of nymphal development, although nymphs cannot complete development when provided only with tomato leaves. 6. Three simple models are presented of feeding behaviour in predatory Heteroptera where the amount of plant feeding either decreases, increases, or is constant as a function of the amount of prey feeding. The models are discussed with reference to the results and the probable multifunctional nature of plant feeding in predatory Heteroptera.     

Rainfall and fluctuating plant populations in relation to distributions and numbers of desert rodents in southern Nevada

Summary Fluctuations in rainfall and size of desert rodent and plant populations for each of five consecutive years were documented on 68 sites in Mojave, Great Basin, and transition desert communities of central-southern Nevada. Post-reproduction rodent densities in the summer usually followed the seasonal patterns of winter annual success the previous spring, in turn directly related to the success of germination the preceding autumn.In the Dipodomys merriami environment, at the lower elevations with relatively low rainfall and high temperatures of the Mojave Desert, D. merriami and D. deserti numbers (indicating success or failure of reproduction) closely followed the seasonal and site patterns of winter annual success. In the Dipodomys microps environment, at the middle and higher elevations with the relatively high rainfall and lower temperatures of the transition and Great Basin deserts, D. microps numbers followed winter annual success patterns in years of high or low rainfall in the months preceding reproduction, but there was reproduction in years of intermediate rainfall whether or not there were winter annuals in the environment. Reproductive patterns of D. merriami in the D. microps environment followed those of D. microps. Perognathus longimembris, the ubiquitous heteromyid of the region, also exhibited both reproductive patterns, depending on whether it was in the D. merriami or the D. microps environment. The Mojave Desert P. formosus, edaphically restricted in the region, followed the patterns of the D. merriami environment and its numbers were highly correlated with winter annual success.Herbaceous perennials, capable of large germinations of plants behaving as biennials or winter annuals, are shown to have large effects on D. merriami numbers. Size of populations of Eurasian annual species of Bromus and Salsola were not correlatable with rodent reproduction patterns.From all patterns in all environments, it is inferred that environmental conditions affecting water balance in the rodents play the key role in initiation of reproduction. Environmental moisture levels during the winter season are usually under the control of rainfall of late autumn-early winter, coincidentally the period of greatest predictability of heavy rains. The herbaceous plants, present in the winter months most years, are available sources of water (and vitamins) at the time of initiation of reproductive activity. For D. microps, identified with the mesic environments of the region, the herbaceous plants may or may not be necessary sources of water for reproduction, depending on the seasonal rainfall regime. For D. merriami, herbaceous plants appear to serve as a water reservoir required for reproduction in its usual environments. The same relationships evidently obtain for the other heteromyids, and the cricetids as a group.Studies conducted under U.S. Atomic Energy Commission Contracts AT(04-1) Gen-12 and AT(11-1) 2307, and at the Nevada Test Site as part of CETO Project 61.5.4     

The Influence of Temporal Changes in Fruit Availability on Diet Composition and Seed Handling in Blue Monkeys (Cercopithecus mitis doggetti)1

We investigated the relation between temporally varying resources, diet composition, and seed-handling behaviors in a group of blue monkeys (Cercopithecus mitis doggetti) in a tropical montane forest of Rwanda. Changes in diet composition were related to concurrent phenological studies of fruit-producing trees, and density and abundance of tree resources within the monkey's home range. Fruit composed nearly 50 percent of the diet. Over 50 percent of the fruits eaten had juicy fleshy pulp. Observations of seed handling behavior provided insights into the role of these animals as potential seed dispersal agents. The monkeys moved the seeds of 29 species out of parent canopies by defecating seeds intact and by potentially carrying seeds in cheek pouches and dropping them later. Seeds of 18 species were found intact in fecal piles. Our study showed community-level phenology patterns did not indicate a decrease in fruit availability during the study period, but an analysis of the preferred fruits consumed by the monkeys showed distinct periods of low fruit availability. The study period included two dry seasons; only one of these produced a period of fruit scarcity for the animals. The animals employed different strategies during times of preferred fruit scarcity. They increased consumption of leaves and other fleshy fruits, and diet diversity increased, or became mainly seed predators and diet diversity decreased. The variable responses of these monkeys to changes in food availability highlights their dietary plasticity and imposes significant variations in their role as potential seed dispersers.     

Functional specialization of <Emphasis Type="Italic">Medicago truncatula</Emphasis> leaves and seeds does not affect the subcellular localization of a recombinant protein

A number of recent reports suggest that the functional specialization of plant cells in storage organs can influence subcellular protein sorting, so that the fate of a recombinant protein tends to differ between seeds and leaves. In order to test the general applicability of this hypothesis, we investigated the fate of a model recombinant glycoprotein in the leaves and seeds of a leguminous plant, Medicago truncatula. Detailed analysis of immature seeds by immunofluorescence and electron microscopy showed that recombinant phytase carrying a signal peptide for entry into the endoplasmic reticulum was efficiently secreted from storage cotyledon cells. A second version of the protein carrying a C-terminal KDEL tag for retention in the endoplasmic reticulum was predominantly retained in the ER of seed cotyledon cells, but some of the protein was secreted to the apoplast and some was deposited in storage vacuoles. Importantly, the fate of the recombinant protein in the leaves was nearly identical to that in the seeds from the same plant. This shows that in M. truncatula, the unanticipated partial vacuolar delivery and secretion is not a special feature of seed cotyledon tissue, but are conserved in different specialized tissues. Further investigation revealed that the unexpected fate of the tagged variant of phytase likely resulted from partial loss of the KDEL tag in both leaves and seeds. Our results indicate that the previously observed aberrant deposition of recombinant proteins into storage organelles of seed tissue is not a general reflection of functional specialization, but also depends on the species of plant under investigation. This discovery will have an impact on the production of recombinant pharmaceutical proteins in plants. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.