Adoption of infant howling monkeys (Alouatta palliata)

During 3 years of continuous field observations on mantled howlers (Alouatta palliata Gray) in Costa Rica we observed five infants without mothers in the main study group. Four of these infants solicited care and two were adopted (one permanently, one temporarily) by lactating females. The other two were carried but not adopted. The fifth neither solicited nor received care. An infant must solicit care to receive care, and female howlers apparently can suckle more than one infant at a time.     

Neue Beobachtungen zur Bestäubung vonOphrys (Orchidaceae) in Südspanien,mit besonderer Berücksichtigung des FormenkreisesOphrys fusca agg.

An investigation of pseudocopulation behaviour in species ofOphrys from southern Spain confirms the close relationship betweenCampsoscolia ciliata (Scoliidae) andOphrys speculum, and betweenEucera nigrilabris (Apoidea) andOphrys tenthredinifera. It could be demonstrated thatEucera barbiventris is the pollinator ofOphrys scolopax subsp.scolopax, whereas other species ofEucera andTetralonia which are active at the same time show no interest at all for the flowers of this species. Special attention was paid to the forms of the taxonomically confusedOphrys fusca group:O. fusca s. str.,O. iricolor, O. omegaifera andO. atlantica. WhileO. fusca s. str. is widespread, small-flowered and has late anthesis,O. iricolor has very large flowers and early anthesis. Each of the four members ofO. fusca agg. in S. Spain is pollinated by a different bee, and selective experiments show that each of these four species of bees is specifically attracted only to one of theOphrys species:Andrena flavipes is the pollinator ofO. fusca s. str.,Colletes cunicularius infuscatus ofO. iricolor, Anthophora atroalba ofO. omegaifera, andChalicodoma parietina ofO. atlantica. These four pollinators belong to 4 different bee families (Andrenidae, Colletidae, Anthophoridae, Megachilidae). As this type of pollination represents a very effective pregamic isolation mechanism, these four taxa ofOphrys fusca agg., at least in southern Spain, behave and should be regarded as genuine species.

     

Warming of experimental plant–pollinator communities advances phenologies,alters traits,reduces interactions and depresses reproduction

Climate change may disrupt plant–pollinator mutualisms by generating phenological asynchronies and by altering traits that shape interaction costs and benefits. Our knowledge is limited to studies that manipulate only one partner or focus on either phenological or trait-based mismatches. We assembled communities of three annual plants and a solitary bee prior to flowering and emergence to test how springtime warming affects phenologies, traits, interactions and reproductive output. Warming advanced community-level flowering onset, peak and end but did not alter bee emergence. Warmed plant communities produced fewer and smaller flowers with less, more-concentrated nectar, reducing attractiveness, and warmed bees were more generalized in their foraging, reducing their effectiveness. Plant–bee interactions were less frequent, shorter and peaked earlier under warming. As a result, warmed plants produced fewer, lighter seeds, indicating pollinator-mediated fitness costs. Climate change will perturb plant–pollinator mutualisms, causing wide-ranging effects on partner species and diminishing the ecosystem service they provide.     

Schooling affects growth in the three-spined stickleback, Gasterosteus aculeatus

Three-spined stickleback fry (mean length 20 mm, mean weight 14 mg) were reared for 14 days alone and in groups of six in a constant per capita water volume. The fish originated from two habitats (rock-pools, sea) of different predation pressure. The fry were fed nauplii of Artemia and commercial aquarium fish food ad libitum. Specific growth rates of solitary and schooling fry differed and were also affected by their origin. The specific growth rates of solitary fry from the sea averaged 1.0% day⁻¹ (length) and 6.0% day⁻¹ (weight) and those of solitary rock-pool fry 1.1 and 6.7%, respectively. For group-reared fish the corresponding values were 1.2% (length) and 6.6% (weight), and 1.3% (length) and 7.6% (weight). The finding that schooling sticklebacks grow faster than solitary ones implies that grouping enhances fitness in stickleback fry under the conditions of our experiments.     

Centris pallida (Hymenoptera: Apidae) male body size decreases across five decades

Historical data suggest that many bee species have declined in body size. Larger-bodied bees with narrow phenological and dietary breadth are most prone to declines in body size over time. This may be especially true in solitary, desert-adapted species that are vulnerable to climate change such as Centris pallida (Hymenoptera: Apidae). In addition, body size changes in species with size-linked behaviours could threaten the prevalence of certain behavioural phenotypes long-term. C. pallida solitary bees are found in the Sonoran Desert. Males use alternative reproductive tactics (ARTs) and are dimorphic in both morphology and behaviour. C. pallida male body size has been studied since the 1970s in the same population. The authors collected body size data in 2022 and combined it with published records from 1974–2022. The authors find a persistent decline in the mean head width of patrolling males, and shifts towards smaller body sizes in the populations of males found foraging and hovering. Both morphs declined in average body size, and the proportion of large-morph males in the population decreased by 8%. Mating males did not decline in mean body size over the last five decades. The authors discuss hypotheses related to the decline in C. pallida male head width. Finally, the authors advocate for C. pallida as an excellent study system for understanding the stability of ARTs with size-linked behavioural phenotypes.     

Egg load and adaptive superparasitism in Anaphes nitens, an egg parasitoid of the Eucalyptus snout-beetle Gonipterus scutellatus

We studied egg production and the occurrence of adaptive superparasitism in Anaphes nitens, an egg parasitoid of the Eucalyptus snout beetle Gonipterus scutellatus. First, we determined whether A. nitens females were synovigenic or pro‐ovigenic. Newly emerged females were allowed to lay eggs alone during 3 days on six fresh egg capsules. A first group of females (n = 25) were killed by freezing and the remaining females (n = 21) were maintained during two extra days with food, but without hosts. Their fecundity was measured by dissection of host eggs and females’ ovarioles. We found that the second group of females increased their fecundity by about 20%, suggesting they were weakly synovigenic. To test for the occurrence of adaptive superparasitism in relation to competitors’ density, we compared the oviposition behaviour of females kept alone, in pairs, or in groups of four during patch visit. Results indicated that the females superparasited significantly more often in this last treatment. Synovigeny and the ability to modulate the use of superparasitism could be mentioned as important attributes that allow A. nitens to efficiently control the pest population.     

Intrinsic competition among solitary and gregarious endoparasitoid wasps and the phenomenon of ‘resource sharing’

1. Intrinsic competition was compared in three species of braconid wasps, the solitary Meteorus pulchricornis Wesmael, and the gregarious Cotesia kariyai (Watanabe) and Cotesia ruficrus Haliday in caterpillars of their common host, the armyworm Mythimna separata Walker. Competition was determined in pair‐wise contests consisting of simultaneous and subsequent parasitisms at various time intervals between the first and second attacks (<1, 24, 48, 72, and 96 h). 2. The experiment revealed that the solitary M. pulchricornis parasitoid was generally superior over the other two gregarious Cotesia species, although, in some cases C. kariyai out‐competed M. pulchricornis when ovipositing first. In contrast, irrespective of the time interval between parasitism and multiparasitism, C. ruficrus always lost in competition with M. pulchricornis. 3. Remarkably, both C. kariyai and C. ruficrus occasionally emerged from the same multiparasitised caterpillar when the time interval between the first and second attacks was small. However, cumulative brood sizes of both species were generally less than when C. kariyai and C. ruficrus developed alone, suggesting that some competition did occur between these two species. 4. Inter‐specific ‘resource sharing’ amongst parasitoid larvae has rarely been described in the literature. In the present study, the conditions in which ‘resource sharing’ in parasitoids can evolve are discussed. Further, we describe differing host usage strategies in parasitoids and how these can affect the outcome of aggressive larval competition.     

Bees and flowers: How to feed an invasive beetle species

Invasive species may exploit a wide range of food sources, thereby fostering their success and hampering mitigation, but the actual degree of opportunism is often unknown. The small hive beetle (SHB), Aethina tumida, is a parasite of honeybee colonies endemic to sub‐Saharan Africa. SHBs have now spread on all habitable continents and can also infest colonies of other social bees. To date, the possible role of solitary bee nests as alternative hosts is unknown. Similarly, flowers as possible alternative food sources are not well understood. Here, we show that SHBs can complete an entire life cycle in association with nests of solitary bees Megachile rotundata. The data also show that flowers can serve as alternative food sources. These results support the opportunistic nature of this invasive species, thereby generating further obstacles for mitigation efforts in the field. It also suggests that SHB invasions may result in more serious consequences for endemic bee fauna than previously thought. This provides further motivation to slow down the global spread of this pest, and to improve its management in areas, where it is established.     

Cardiovascular baroreflex circuit moonlights in sleep control

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