Mg/Ca ratio of Globorotalia tumida and subsurface temperature reconstruction for ODP Site 130-806

The tropical Pacific thermocline strength, depth, and tilt are critical to tropical mean state and variability. During the early Pliocene (~3.5 to 4.5 Ma), the Eastern Equatorial Pacific (EEP) thermocline was deeper and the cold tongue was warmer than today, which resulted in an mean state with a reduced zonal sea surface temperature gradient, or El Padre. However, it is unclear whether the deep thermocline was a local feature of the EEP or a basin-wide condition with global implications. Our measurements of Mg/Ca of Globorotalia tumida in a western equatorial Pacific site indicate Pliocene subsurface temperatures warmer than today; thus, El Padre included a basin-wide thermocline that was relatively warm, deep, and weakly tilted. At ~4 Ma, thermocline steepening was coupled to cooling of the cold tongue. Since ~4 Ma, the basin-wide thermocline cooled/shoaled gradually, with implications for thermocline feedbacks in tropical dynamics and the interpretation of TEX86-derived temperatures.

Prevalencia del Pequeño Escarabajo de la Colmena (PEC), (Aethina tumida), en el municipio de Nindirí, departamento de Masaya, en el periodo de agosto 2015

El presente trabajo fue realizado con el objet iv o de determinar la pre valencia del Pequeño Escarabajo de la Colmena (PEC) - Aethina tumida - , en el municipio de Nindirí del departamento de Masaya y observar las prácticas que usan los productore s para el control de este parásito, para esto se muestrearon un total de 7 apiarios distribuidos en tres comunidades, El portillo (1) , Cofradía (3) y Santa Juana (3) ; se muestrearon un total de 41 colmenas . P ara determinar la presenci a del PEC en sus diferentes estadios se realiz ó muestro por cada secci ón de la colmena (tapa, cámara melaría y de cr ía , y piso de la colmena) , un segundo muestreo se efectuó frente a la colmena a nivel del suelo . Los resultado s obtenidos r eportan que e n la comunidad del Portillo se encontró presencia de 3 larv as y 1 adultos en tapa y (7 adultos) piso de la colmena, y solamente adultos (3) en la cámara de cría. En Cofradía fue evidente la presencia de adultos (1) en la alza melaría, (1) cámara de cría y (29) piso de la colmena, la fase larvaria (8) a nivel del p iso de la colmena y la fase pupar (3) en los primeros 20 cm de suelo frente a la piquera colmena. Para Santa Juana la presencia de adultos (6) fue localizado en el piso de la colmena y la presencia de pupas (4) a nivel del suelo. Las prácticas de transhuma ncia, compra de colmenas y abejas reinas procedentes de apiarios no certificados ha permitido la diseminación del PEC en estas comunidades. Las prácticas de encalado, eliminación manual de adultos del PEC y colmenas débiles así como la remoción de suelo so n las más implementadas para el control del PEC en estas comunidades, no se documentaron medidas de prevención para el monitoreo del pequeño escarabajo de la colmena.

The alternative Pharaoh approach: stingless bees mummify beetle parasites alive

Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and their parasites.

Honey Bee Apis mellifera Parasites in the Absence of Nosema ceranae Fungi and Varroa destructor Mites

Few areas of the world have western honey bee (Apis mellifera) colonies that are free of invasive parasites Nosema ceranae (fungi) and Varroa destructor (mites). Particularly detrimental is V. destructor; in addition to feeding on host haemolymph, these mites are important vectors of several viruses that are further implicated as contributors to honey bee mortality around the world. Thus, the biogeography and attendant consequences of viral communities in the absence of V. destructor are of significant interest. The island of Newfoundland, Province of Newfoundland and Labrador, Canada, is free of V. destructor; the absence of N. ceranae has not been confirmed. Of 55 Newfoundland colonies inspected visually for their strength and six signs of disease, only K-wing had prevalence above 5% (40/55 colonies = 72.7%). Similar to an earlier study, screenings again confirmed the absence of V. destructor, small hive beetles Aethina tumida (Murray), tracheal mites Acarapis woodi (Rennie), and Tropilaelaps spp. ectoparasitic mites. Of a subset of 23 colonies screened molecularly for viruses, none had Israeli acute paralysis virus, Kashmir bee virus, or sacbrood virus. Sixteen of 23 colonies (70.0%) were positive for black queen cell virus, and 21 (91.3%) had some evidence for deformed wing virus. No N. ceranae was detected in molecular screens of 55 colonies, although it is possible extremely low intensity infections exist; the more familiar N. apis was found in 53 colonies (96.4%). Under these conditions, K-wing was associated (positively) with colony strength; however, viruses and N. apis were not. Furthermore, black queen cell virus was positively and negatively associated with K-wing and deformed wing virus, respectively. Newfoundland honey bee colonies are thus free of several invasive parasites that plague operations in other parts of the world, and they provide a unique research arena to study independent pathology of the parasites that are present.

Hit-and-run trophallaxis of small hive beetles

Some parasites of social insects are able to exploit the exchange of food between nestmates via trophallaxis, because they are chemically disguised as nestmates. However, a few parasites succeed in trophallactic solicitation although they are attacked by workers. The underlying mechanisms are not well understood. The small hive beetle (=SHB), Aethina tumida, is such a parasite of honey bee, Apis mellifera, colonies and is able to induce trophallaxis. Here, we investigate whether SHB trophallactic solicitation is innate and affected by sex and experience. We quantified characteristics of the trophallactic solicitation in SHBs from laboratory-reared individuals that were either bee-naïve or had 5 days experience. The data clearly show that SHB trophallactic solicitation is innate and further suggest that it can be influenced by both experience and sex. Inexperienced SHB males begged more often than any of the other groups had longer breaks than their experienced counterparts and a longer soliciting duration than both experienced SHB males and females, suggesting that they start rather slowly and gain more from experience. Successful experienced females and males were not significantly different from each other in relation to successful trophallactic interactions, but had a significantly shorter soliciting duration compared to all other groups, except successful inexperienced females. Trophallactic solicitation success, feeding duration and begging duration were not significantly affected by either SHB sex or experience, supporting the notion that these behaviors are important for survival in host colonies. Overall, success seems to be governed by quality rather than quantity of interactions, thereby probably limiting both SHB energy investment and chance of injury (<1%). Trophallactic solicitation by SHBs is a singular example for an alternative strategy to exploit insect societies without requiring chemical disguise. Hit-and-run trophallaxis is an attractive test system to get an insight into trophallaxis in the social insects.

Investigation of Quaternary diatoms in sediment core CRP-1 from the Ross Sea, Antarctica

In the first season of drilling, the Cape Roberts Project (CRP) recovered one drillcore (CRP-l) from Roberts Ridge in western McMurdo Sound, Ross Sea, Antarctica Diatom biostratigraphy places the upper six lithostratigraphic units (Units 1.1, 2.1, 2.2, 2.3, 3.1, and 4.1) of CRP-l (0.0 to 43.15 mbsf) within the Quaternary. Both non-marine and marine Quaternary diatoms occur in variable abundance in the Quaternary interval of CRP- 1 Biostratigraphic data resolve two Quaternary time slices or events within CRP-1. Marine diatom assemblages in Units 4.1 and 3.1 represent sedimentation within the diatom Actinocyclus ingens Zone (1.35 to 0.66 Ma). Further refinement of the age of Unit 3.l places deposition in the interval 1.15 to 0.75 Ma based on the common occurrence of Thalassiosira elliptipora and correlation to the Southern Ocean acme of this taxon The absence of ActiActinocyclus ingens and the presence ot Thalassiosira antarctica in Unit 2.2 require a younger zonal assignment for this interval, within the diatom Thalassiosira lentiginosa Zone (0.66 to 0.0 Ma). A new diatom species. Rouxia leventerae, is described from marine assemblages of Units 2.2, 2.3, 3.1, and 4.l. Lithostratigraphic Unit 3.1 (33.82 to 31.89 mbsf) is a bryozoan-dominated skeletal-carbonate facies. Low abundance of Fragilariopsis curta and Fragilariopsis cylindrus within this unit combined with the relatively high abundance of species associated with open water indicates deposition in waters that remained ice free for much or all of the year Diatom assemblages suggest carbonate deposition in Unit 3.1 is linked to a significant early Pleistocene event in McMurdo Sound, when elevated surface-water temperatures inhibited the formation of sea ice.

Relative abundance and ranges of selected diatoms from Pliocene-Pleistocene sections of ODP Leg 177, Atlantic sector of the Southern Ocean

During Ocean Drilling Program (ODP) Leg 177, seven sites were drilled aligned on a transect across the Antarctic Circumpolar Current in the Atlantic sector of the Southern Ocean. The primary scientific objective of Leg 177 was the study of the Cenozoic paleoceanographic and paleoclimatic history of the southern high latitudes and its relationship with the Antarctic cryosphere development. Of special emphasis was the recovery of Pliocene-Pleistocene sections, allowing paleoceanographic studies at millennial or higher time resolution, and the establishment of refined biostratigraphic zonations tied to the geomagnetic polarity record and stable isotope records. At most sites, multiple holes were drilled to ensure complete recovery of the section. A description of the recovered sections and the construction of a multihole splice for the establishment of a continuous composite is presented in the Leg 177 Initial Reports volume for each of the sites (Gersonde, Hodell, Blum, et al., 1999). Here we present the relative abundance pattern and the stratigraphic ranges of diatom taxa encountered from shore-based light microscope studies completed on the Pliocene-Pleistocene sequences from six of the drilled sites (Sites 1089-1094). No shore-based diatom studies have been conducted on the Pliocene-Pleistocene sediments obtained at Site 1088, located on the northern crest of the Agulhas Ridge, because of the scattered occurrence and poor preservation of diatoms in these sections (Shipboard Scientific Party, 1999b). The data included in our report present the baseline of a diatom biostratigraphic study of Zielinski and Gersonde (2002), which (1) includes a refinement of the southern high-latitude Pliocene-Pleistocene diatom zonation, in particular for the middle and late Pleistocene, and (2) presents a biostratigraphic framework for the establishment of age models of the recovered sediment sections. Zielinski and Gersonde (2002) correlated the diatom ranges with the geomagnetic polarity record established shipboard (Sites 1090 and 1092) (Shipboard Scientific Party, 1999c, 1999d) and on shore (Sites 1089, 1091, 1093, and 1094) by Channell and Stoner (2002). The Pliocene-Pleistocene diatom zonation proposed by Zielinski and Gersonde (2002) relies on a diatom zonation from Gersonde and Bárcena (1998) for the northern belt of the Southern Ocean. Because of latitudinal differentiation of sea-surface temperature, nutrients, and salinity between Antarctic and Subantarctic/subtropical water masses, the Pliocene-Pleistocene stratigraphic marker diatoms are not uniformly distributed in the Southern Ocean (Fenner, 1991; Gersonde and Bárcena, 1998). As a consequence, Zielinski and Gersonde (2002) propose two diatom zonations for application in the Antarctic Zone south of the Polar Front (Southern Zonation, Sites 1094 and 1093) and the area encompassing the Polar Front Zone (PFZ) and the Subantarctic Zone (Northern Zonation, Sites 1089-1092). This accounts especially for the Pleistocene zonation where Hemidiscus karstenii, whose first abundant occurrence datum and last occurrence datum defines the subzonation of the northern Thalassiosira lentiginosa Zone, occurs only sporadically in the cold-water realm south of the PFZ and thus is not applicable in sections from this area. However, newly established marker species assigned to the genus Rouxia (Rouxia leventerae and Rouxia constricta) are more related to cold-water environments and allow a refinement of the Pleistocene stratigraphic zonation for the southern cold areas. A study relying on quantitative counts of both Rouxia species confirms the utility of these stratigraphic markers for the identification of sequences attributed to marine isotope Stages 6 and 8 in the southern Southern Ocean (Zielinski et al., 2002).

Stable isotope record of planktonic foraminifera from sediment core MD96-2085

A high-resolution (~4-5cm/kyr) giant piston core record (MD962085) retrieved during an IMAGES II-NAUSICAA cruise from the continental slope of the southeast Atlantic Ocean reveals striking variations in planktonic foraminifer faunal abundances and sea-surface temperatures (SST) during the past 600 000 yr. The location and high-quality sedimentary record of the core provide a good opportunity to assess the variability of the Benguela Current system and associated important features of the ocean-climate system in the southeast Atlantic. The planktonic foraminifer faunal abundances of the core are dominated by three assemblages: (1) Neogloboquadrina pachyderma (right coiling) + Neogloboquadrina dutertrei, (2) Globigerina bulloides, and (3) Globorotalia inflata. The assemblage of N. pachyderma (right coiling) + N. dutertrei shows distinctive abundance changes which are nearly in-phase with glacial-interglacial variations. The high abundances of this assemblage are associated with major glacial conditions, possibly representing low SST/high nutrient level conditions in the southwestern Africa margin. In contrast, the G. bulloides and G. inflata assemblages show greater high-frequency abundance change patterns, which are not parallel to the glacial-interglacial changes. These patterns may indicate rapid oceanic frontal movements from the south, and a rapid change in the intensity of the Benguela upwelling system from the east. A single episode of maximum abundances of a polar water species N. pachyderma (left coiling) occurred in the beginning of stage 9 (~340-330 kyr). The event of the maximum occurrence of this species shown in this record may indicate instability in the Benguela coastal upwelling, or the Antarctic polar front zone position. A winter season SST estimate using transfer function techniques for this record shows primarily glacial-interglacial variations. The SST is maximal during the transitions from the major glacial to interglacial stages (Terminations I, II, IV, V), and is associated with the abundance maxima of a warm water species indicator Globigerinoides ruber. Cross-spectral analyses of the SST record and the SPECMAP stack reveal statistically significant concentrations of variance and coherencies in three major orbital frequency bands. The SST precedes changes in the global ice volume in all orbital frequency bands, indicating a dominant southern Hemispheric climate effect over the Benguela Current region in the southeast Atlantic.