Age-dependent functional response of Aphidius matricariae (Hymenoptera: Braconidae) on tobacco aphid,Myzus persicae nicotianae (Hemiptera: Aphididae)

This study was performed to investigate the age-dependent functional response of Aphidius matricariae Haliday (Hymenoptera: Braconidae) at varying densities of tobacco aphid, Myzus persicae nicotianae Blackman (Hemiptera: Aphididae). Six densities (2, 4, 8, 16, 32, and 64 numbers) of third instar nymphs of M. persicae nicotianae were daily exposed to one pair of 1-day-old A. matricariae until the parasitoid female died. Each host aphid density was replicated 10 times. The experiments were conducted at constant environmental conditions (25 ± 1 °C, 70 ± 5% RH and 16:8h L:D photoperiod). The logistic regression model demonstrated that the functional response of A. matricariae was type III in the second day and type II in the first day and from third to the end of adult parasitoid lifetime. The handling time (T_h) was lowest in the first day (0.2305 h) and highest in the sixth day (2.9296 h) of the parasitoid’s life. The searching efficiency (a) values were 0.0573, 0.0649, 0.0503, 0.0229, and 0.0077 h^?1 in the first, third, fourth, fifth, and sixth days of the parasitoid’s life, respectively. Also, the b value for type III functional response was 0.0147 in the second day. The values of maximum attack rate (T/T_h) ranged from 104.12 nymphs/24 h in the first day to 19.8 nymphs/24 h in the sixth day of parasitoid’s life. Based on the results, A. matricariae showed a high potential to control the population of tobacco aphid and the highest efficiency gained in the first half of the female parasitoid life.     

Study on some biological characteristics of Tetrastichus gallerucae (Hym. Eulophidae), important parasitoid of Elm leaf beetle eggs in Kerman,Iran

In this study, a number of biologic characteristics of Tetrastichus gallerucae, the most important natural enemy of Xanthogaleruca luteola (Col.: Chrysomellidae), were studied. Experiments were carried out in growth room with a temperature of 25°C±1°C, relative humidity of 60%±5% and light period of 16L:8D. The results demonstrated the following outcomes: without food and host egg, the longevity of male and female bees was respectively, 1.23 and 1.35 days. On the host egg, their longevities were 3.85 and 6.02 days, respectively. On rarefied honey their longevities were 14.04 and 24.74 days, respectively and on the host eggs together with rarefied honey, their longevities were 13.4 and 34.72 days, respectively. The average growth period times in the egg of elm leaf beetle of male and female bees were 12.97 and 12.63 days, respectively. The percentage of female bees decreases as the longevity of the insects increases. These bees lay eggs in the 1–9-day-old eggs of elm leaf beetle but 1-day-old eggs of the host are preferred by T. gallerucae.     

Intra‐community coalitionary lethal attack of an adult male southern muriqui (Brachyteles arachnoides)

We report on the first evidence of intra‐community coalitionary lethal aggression in muriquis (Brachyteles). The event occurred in southern muriquis (Brachyteles arachnoides) during a long‐term study (>15 years) of two social groups inhabiting mostly pristine Atlantic forest habitat in the Parque Estadual Carlos Botelho, southern São Paulo State, Brazil. The attack took place deep in the core area of the Group Caetê home range. Tense agonistic behaviors and vocalizations preceded the lethal coalitionary attack, and the tension increased over a 36–48 hr period. One adult female and two unidentified individuals also took part in a coalition led by six adult males. The members of the coalition collectively approached, embraced, immobilized and repeatedly bit the entire body of an adult male, resulting in severe bleeding injuries and the victim's death in less than 1 hr after the attack commenced. Combined ecological, behavioral and spatial data related to the event indicate that this was an intra‐community attack and suggest social tensions related to mating competition as the proximate trigger of the coalitionary killing. The attack resembled those reported for chimpanzees, with clear numeric superiority and a low risk of injury to aggressors, resulting in the death of a lone conspecific victim. This observation (n=1) is suggestive of a capacity for escalated aggression in muriquis and reinforces arguments for the potential adaptive significance of intra‐community aggression in male philopatric societies, as reported for spider monkeys and chimpanzees. These characteristics challenge the view of the muriquis as a peaceful primate and support the general hypothesis that imbalances of power contribute to intra‐specific killing in primates, such as chimpanzees and humans. Am. J. Primatol. 71:860–867, 2009. © 2009 Wiley‐Liss, Inc.     

Measuring the Toughness of Primate Foods and its Ecological Value

The mechanical properties of plant foods play an important role in the feeding process, being one of many criteria for food acceptance or rejection by primates. One of the simplest justifications for this statement is the general finding that primates tend to avoid foods with high fiber. Although fiber is largely tasteless, odorless, and colorless, it imparts texture, a sensation in the mouth related to the physical properties of foods. All primates encounter such mechanical resistance when they bite into plant food, and studies on humans show that an incisal bite facilitates quick oral assessment of a property called toughness. Thus, it is feasible that primates make similar assessments of quality in this manner. Here, we review methods of measuring the toughness of primate foods, which can be used either for making general surveys of the properties of foods available to primates or for establishing the mechanisms that protect these foods from the evolved form of the dentition.     

Fission–Fusion Dynamics in Southern Muriquis (Brachyteles arachnoides) in Continuous Brazilian Atlantic Forest

Fission–fusion social dynamics, the spatiotemporal variance in subunit size, composition, and cohesion, are the subject of considerable interest owing to their complex nature and widespread appearance in the primate order. We here aim to describe the nature of fission–fusion dynamics in a population of egalitarian southern muriquis inhabiting a relatively undisturbed extension of mildly seasonal Brazilian Atlantic forest to provide insights into the functions of fission–fusion dynamics and to examine the constraints on and opportunities for associations among individuals. We collected instantaneous scan samples and ad libitum data over a total of 13 mo in 2 yr (1599 observation hours) on subunit size at 2 spatiotemporal scales (party and nomadic party), party composition, spatial cohesion, and the behavioral context of fission–fusion events. These southern muriquis exhibited high levels of fission–fusion with significant variation in party size, cohesion, and composition. The group was weakly cohesive with a small mean party size (3.74 adults, 5.32 all individuals) and nomadic party size (13.73 adults, 19.38 all individuals). Mixed parties were the most frequently observed party type, although the high frequency of all-male parties suggests strong relationships based on philopatry and a mating strategy under scramble competition. We compare fission–fusion dynamics across populations of Brachyteles and highlight the striking continuum of these dynamics in the genus. We make interspecific comparisons with Ateles and Pan, with well documented high levels of fission–fusion, and demonstrate interspecific variation and convergence in grouping patterns.     

Possible Fruit Protein Effects on Primate Communities in Madagascar and the Neotropics

Background

The ecological factors contributing to the evolution of tropical vertebrate communities are still poorly understood. Primate communities of the tropical Americas have fewer folivorous but more frugivorous genera than tropical regions of the Old World and especially many more frugivorous genera than Madagascar. Reasons for this phenomenon are largely unexplored. We developed the hypothesis that Neotropical fruits have higher protein concentrations than fruits from Madagascar and that the higher representation of frugivorous genera in the Neotropics is linked to high protein concentrations in fruits. Low fruit protein concentrations in Madagascar would restrict the evolution of frugivores in Malagasy communities.

Methodology/Principal Findings

We reviewed the literature for nitrogen concentrations in fruits from the Neotropics and from Madagascar, and analyzed fruits from an additional six sites in the Neotropics and six sites in Madagascar. Fruits from the Neotropical sites contain significantly more nitrogen than fruits from the Madagascar sites. Nitrogen concentrations in New World fruits are above the concentrations to satisfy nitrogen requirements of primates, while they are at the lower end or below the concentrations to cover primate protein needs in Madagascar.

Conclusions/Significance

Fruits at most sites in the Neotropics contain enough protein to satisfy the protein needs of primates. Thus, selection pressure to develop new adaptations for foods that are difficult to digest (such as leaves) may have been lower in the Neotropics than in Madagascar. The low nitrogen concentrations in fruits from Madagascar may contribute to the almost complete absence of frugivorous primate species on this island.     

Toxicity of fenitrothion, an organophosphorus pesticide, against summer population of sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae)

The sunn pest are a group of insect representing several genera of the shield bug (Scutelleridae) and stink bug (Pentatomidae) families, with the species Eurygaster integriceps being the most economically important. The sunn pest is a major pest of wheat and barley in central and western Asia and it accounts for annual losses of 20-30% for barley and up to 100% for wheat. In the recent decades problems have intensified largely due to change in farming practices. Thus this pest threatens food security and reduces the stability of traditionally wheat-based agricultural systems. In order to control pest, the major organophosphorus insecticide used is fenitrothion. So, the aim of the current study was to determine toxicity of fenitrothion against summer population of adult sunn pest. Insecticide toxicity was measured using a topical bioassay. To do so, the toxin was dissolved in acetone and six concentrations of toxin including 25, 50, 100, 150, 175 and 200 ppm were prepared. Insects were treated on the pronotum with one micro litre aliquots of insecticide in acetone (for treatments) or acetone alone (for control). The dose-mortality relationship was assessed from above mentioned doses with 30 insects treated per dose. After treatment, insects were maintained at laboratory conditions and mortality was recorded after 48 hours. Results were corrected for control mortality with Abbott's formula and then analyzed and toxicity determined. The obtained results showed that LD10, LD50, and LD90 were 34.7, 90.43, and 235.5, respectively.